Montgomery County (Maryland)
Montgomery County is in the Capital Region of Maryland, right on the border with Washington, D.C., and is home to about one million people. It is one of the wealthiest counties in the country, in no part due to how highly educated its populace is—it holds the country's record for post-graduate degrees per capita. Its largest cities such as Rockville, Bethesda, Gaithersburg, Silver Spring, Germantown, many of which remain unincorporated, are major business, shopping, and entertainment centers for the Washington, D.C. metro area. The county is quite international, with more than a quarter of its population being foreign-born, with especially large Southeast Asian and Central American communities. While many of its residents commute to D.C. to work in government or related fields, the suburban cities support huge amounts of jobs of their own, with the county being a major hub especially for the biotech, hotel, and retail sectors.
Traffic comes in from the northwest on I-270, and pours in from east and west on the habitually clogged Beltway, I-495, which brings in drivers from I-95 in the northeast, and from Virgina to the south. There are no highways leading here from Washington, D.C. (and this contributes greatly to the traffic). The major arteries from west to east include Wisconsin Ave, Connecticut Ave, and Georgia Ave.
Montgomery County is served by both the northeast and northwest sections of the D.C. Metro Red Line . The northwest section includes stops right in the thick of Friendship Heights, Bethesda, Rockville, and Gaithersburg; the northeast section in Takoma Park, Silver Spring, and Wheaton.
Generally it's easiest to take the Metro from D.C. and then transfer to bus from the Metro stop, but there are a few major Metrobus  routes to Montgomery County from the city: #30-36  run up Wisconsin Ave to the Friendship Heights Metro station, and #70-71  run up Georgia Ave to the Silver Spring Metro station. From these stations you will have to transfer to another bus to keep going.
The U.S. is an automotive country, and Montgomery County, despite having quite impressive public transport, is no exception. Driving is without a doubt the most convenient way of getting around, but be forewarned that the county has some of, if not the worst traffic in the entire nation (it vies for that dubious distinction with neighboring counties in Virginia). The aforementioned north-south arteries, as well as the east-west Beltway and northwesterly I-270 and the Rockville Pike between Bethesda and Rockville are the main routes around the densely populated parts of the county.
Montgomery County has an excellent bus system, and while it may take you a while to get where you are going, you can reach just about any major destination in the county by bus alone. WMATA's Metrobus  has a respectable network of bus routes right in the inner suburbs, while Ride On Bus  is the county bus service, with very comprehensive coverage of the densely populated portion of the county. Note that WMATA's SmarTrip card works for Ride On buses as well as the Metro and Metrobus.
For sightseeing, you are best off heading south into D.C., which has more major attractions than you can shake a stick at. But if you've been there, done that, there are some off-the-beaten-path attractions in Montgomery County. There are several quite unusual destinations that can make for a good trip. The National Mormon Temple in Kensington is enormous and impressive, famously drawing comparisons to the Oz's Emerald Palace from daredevil Beltway graffiti artists. You can't go inside, but you can take pictures from the outside and learn about the temple and the Church of Latter Day Saints at its visitor center. Nearby in Forest Glen is the very weird collection of exotic buildings at the half-abandoned National Park Seminary: a Japanese pagoda, a Swiss-style castle, a Dutch windmill, etc. Glen Echo is a unique "antique amusement park," still operating a carousel, a Spanish ballroom for dance lessons and events, dramatic theater, and other attractions.
The one truly big attraction worth seeking out, though, is the imposing Great Falls on the Potomac River in the Chesapeake and Ohio Canal National Historical Park. The Maryland side boasts the best views of this massive collection of rapids and waterfalls, and makes for a great picnic. The park itself would be worth visiting even without the draw of the falls for its historic charm. For more outdoor attractions, try Wheaton's lovely Brookside Gardens.
Rock Creek Park
Given how affluent and international Montgomery County is, it's hardly surprising that there is a lot of good food to be had. For a downtown dining experience, Bethesda is the unchallenged leader, with a huge variety of mid-range and upscale restaurants, running the gamut from Spanish tapas to Maryland crabs, gourmet Indian to Philly cheesesteaks, with a host of great options in between. There are gems throughout the other major cities, like Silver Spring, Rockville, Gaithersburg, etc.—albeit quite crowded out by legions of mid-range chain restaurants both in the respective downtown areas and on the endless strip malls throughout.
If you have a taste for cuisines around the world, you are in luck, and won't have to spend too much money. Wheaton has arguably the best cheap ethnic eats in the whole D.C. metro area, especially for great Asian and Central American food, due to its significant Chinese, Vietnamese, Thai, Guatemalan, Honduran, and especially Salvadoran communities. For each of those categories, you simply will not find better outside Wheaton. It's not too shabby for Korean, Ethiopian, Peruvian, or even Scottish, for that matter. Rockville, Silver Spring, and Takoma Park cannot boast the sort of density of ethnic restaurants as Wheaton, but are nonetheless also good bets for Asian, African, and Latin American food.
As with restaurants, Bethesda has the county's largest and liveliest nightlife scene, with a ton of bars and a good handful of night clubs. In the past decade, however, Silver Spring has decided to become a legitimate challenger, and you'll find plenty to do there after hours right in its downtown section. The latter is slightly cheaper and much more diverse. For an even more diverse and certainly more offbeat experience, Takoma Park has only a few options, but they are a lot of fun.
You won't have trouble finding your basic bar in any of the other major communities throughout the community, but options are fairly limited by way of clubs. Not to worry, though, since the county is adjacent to D.C.!
Hotels, of which there are many—Marriott is headquartered in Bethesda—are to be found mostly around the county's major downtown cores. Those of Bethesda and and Silver Spring cater more to tourists, looking to enjoy easy access to the D.C. Metro and the nearby restaurants and entertainment, while those of Rockville, the Rockville Pike, Gaithersburg, and Germantown cater more to business travelers. If you are looking for roadside motels off I-270 or the Beltway, you might actually be surprised at just how few options there are—you'll likely need to head a good ways off the highway into town.
Aside from car accidents, which are indeed a problem, Montgomery County is about as safe a highly populated area as you'll find anywhere in the United States. The gang crime and robbery problems that plague the nation's capital simply do not spill across the district borders, with a robbery rate of just 100 per 100,000 residents in 2007. You might occasionally hear murmurs of Silver Spring or Wheaton having a crime problem, but this notion simply does not align with reality as shown by police statistics. Unless wandering alone late at night in an isolated part of a deserted downtown area, you are quite unlikely to become a victim of a crime.
The obvious nearby destination is of course Washington, D.C., the capital of the U.S., home to a mind-bogglingly long list of attractions, some of which are a either short drive down Connecticut Ave or a ride on the Metro's Red Line. The National Zoo, the Hillwood Estate, the Uptown Theatre, and the National Cathedral are all within easy striking distance from Bethesda. If you are east of Rock Creek Park by Silver Spring or Takoma Park, it's a short drive down Blair Rd to North Capitol St to get to D.C.'s Little Vatican to see the National Shrine. To get to the National Mall, or the city's principal wining and dining centers, you'll have to travel a bit further, but the Metro will take you right there without hitch.
There is more to see other than the obvious neighbor to the south, though. Baltimore is a city very rich in history, museums, and seafood, and is a very short trip up I-95. Staying even closer to Montgomery County, try going east on the Beltway into Prince George's County to see the Nasa Goddard Visitor Center at Greenbelt, or Six Flags Amusement Park in Largo.