sport
In May the Ruhr Marathon (http://www.karstadt-marat...) takes place with about 20.000 athletes and 100.000 viewers. You must have seen it.
Football/soccer is the most popular sport in the region. Every town has several pitches and in the summer there are few grassy areas not used for playing. The Ruhr also has several professional football teams, creating at times an intense rivalry. The most intense is between supporters of Borussia Dortmund and Schalke 04. As a rule of thumb you should avoid wearing football jersies in blue and white in Dortmund and yellow and black in Gelsenkirchen. The rivalry between these two teams rarely turns into violence, but the atmosphere can get a bit hostile, especially if you don't understand the people.
Bochum, Oberhausen and Duisburg also have professional teams, but these are considered non-contenders by supporters of the two big teams. Matchdays are between Friday and Sunday and can lead to heavy traffic at the roads and public transport. You should behave like the locals and avoid the playing cities on match day unless you have tickets for the match.
Excellent conditions for cycling offer the Ruhrtalradweg (http://www.ruhrtalradweg.de/) with a length of about 230 kilometers through rural regions, the Emscher Radweg leads 225 km beside river Emscher and Rhein-Herne-Canal through industrial panorama. For short trips Lake Kemnade and Lake Baldeney not at the weekend as well as the Ore-Route Erzbahntrasse - without any crossing from Bochum Westpark to river Emscher with connection from October 2008 to Emscher-Route and Kray-Wanner-Route 5 street-crossings from Colliery Zollverein towards to the city of Wanne-Eickel with connection to Ore-Route. Both routes offer an excellent view on industry surroundings, settlements and suburbs.
Inline scating you can do very well around Lake Kemnade 910 km at the southern limits of Bochum and Lake Baldeney 16 km at the southern limits of Essen. But avoid to visit this locations at the weekend - it will be too crowded.
For jogging, the routes above are very suitable but also there are Nordsternpark at Gelsenkirchen, Gyserberg-Park at Herne and Rombergpark at Dortmund for all of them entry admission free
theatre, musicals
The municipal Theatre in Bochum has an excellet repution.
A lot of private Theatres in all cities offer excellent shows. Ask at the tourist offices of the cities for addresses and shows.
Musical Starlight Express (http://www.starlight-expr...) in Bochum is amoung the most successful musicals worldwide.
Visit Colosseum Theatre (http://www.colosseumtheat...) in Essen. It is a former production hall with an wonderful industrial ambiente.
The play and concert festival Ruhr Triennale (http://www.ruhrtriennale....) offers a wide range of events spread all over the region.
Another example for the re-use of a former industrial building is the Jahrhunderhalle Hall of the Century in Bochum - one of the most extraordinary stages worldwide.
festivals
Every year at the first weekend of summer schoolout starts Bochum Total (http://bochumtotal.de/ind...). For 4 days the city turns into a stage for rock music.