"MG", as it is often abbreviated, is mostly reknown for it's Soccer Club, Borussia Mönchengladbach. Though inhabited by more than a quarter million people it appears to be a small town due to infrastructure, culture and "spirit". There is very limited public traffic (esp. at night), very few clubs and pubs, no arthouse cinemas, no "scenes" etc. The metropolises of Ruhr, Cologne and Düsseldorf tend to cause a certain "brain drain" from MG so it appears to some as a kind of suburb to those - though again poorly connected in terms of public traffic.
Mönchengladbach has a bus system but it's weak. From 8 pm it's of no practical help and from 11 pm there are no buses. Buses start from 5 am (9am on Sundays!). On Fridays and Saturdays there is a Night Bus from the party area Alter Markt / Waldhausener Str. to the outskirts, but only until 3 am. You'll always find a taxi of course but they can be costly. Biking is advisable only from April to October, watch out for sudden weather changes. Distances within the center are easily walked, but Rheydt and the outskirts are not.
Borussia Mönchengladbach - The club is currently in the Bundesliga. The stadium capacity is 54.000 people, you might like to join a match, especially versus Bayern München, 1.FC. Köln, or Borussia Dortmund
On Wednesday nights usually you will start at the Mezcalito at about 9pm, pay an entry fee of 3 Euro and drink half price drinks. Comfortably numb you will then stagger to the Rossi and finish your work. Sometimes there are Open Jam Sessions or Live Concerts at the Projekt 42.
On Thursday there are occasional "Poetry Slams" at the Projekt 42 (german), better check the HP before.
Anyway, there are some shops worth being mentioned:
If you like german bread: Cafe Ö, Marktstieg 8, Very close to the "Alter Markt", is a non-chain-bakery and cafe. They do "handcrafted", organic, whole wheat bread. That's what germans miss when they're abroad (some even prior to beer).
If you consider tea bags a crime and are in need of the real stuff: "Tee Gschwender", Hindenburgstr., at the "Theater Galerie" will give you sweet relief.
You'll find a Chucks and Vans shop at the Theater Galerie, too.
If you're into Punk, Hardcore, Ska etc. music and clothes, pay a visit to Nightmare Records, Waldhausener Str. (Altstadt). edit
Das Cafe (old fashioned student's Cafe, very popular italian waiter), Wallstr. 19 (Between Hindenburgstr. and Viersener Str.). 10 - 01:00. food starts at 3,10 € (Try their 'Baguette') Hot Drinks 1,90 €. edit
Mokka (Cafe and restaurant, crowded at lunchtime), Stephanstr. (Between Hindenburgstr. and Bismarckplatz). edit
Shiva Lounge (shanti Restaurant and hangout. Shishas available), Waldhausener Str. 31 (Altstadt), ☎ 02161.175634. edit
Mezcalito (Mexican Bar), Gasthausstr. 30 (Altstadt). Wd,Th 20:00 - 03:00, Fr, Sat 20:00 - 03:00. Wednesday/Thursday Half Price on all drinks. edit
Nacht (House Club), Waldhausener Str. 23 (Altstadt). Fr, Sat 23:00 - 05:00. edit
Projekt 42 (Underground Club), Waldhausener Str. 42 (Altstadt), . Fr, Sat, 23 - 5:00, Wd 21 - 1:00. edit
Rossi (Classix Club), Waldhausener Str. 65 (Altstadt). Wds, Fr, Sa 22:00 - 05:00. edit
Roots Club (Rock, Metal Hardcore, some HipHop), Aachener Str 23 (Altstadt), . Smaller Live and Dance Club, occasional concertsedit
Galerie Cafe / Message (Rock Cafe and Club, best club concerts in town), Sophienstr. 17 (back exit main station, keep right, turn right at McD., turn left after few streets), . Check their HP for concerts! Surprises Guaranteed! food from 5pm - 11 pm drinks on fr. and sat -min. 3 am closed on sun and monedit
Graefen clubbing (Sports Bar and Disney style rock cafe), Alter Markt. A little overstyled, Fashionable beer, big TV screen.edit