Could you help me identify this bug?

There were 2-3 in the common area of my dorm one morning (I suppose they were attracted to the light), so we closed the windows at night. More of them kept appearing and after squatting a good number of them yesterday they seem to have come back (breeding very rapidly I guess).
http://img3.imageshack.us/img3/7193/bug1h.png
http://img189.imageshack.us/img189/7020/bug2.png

They're quite small, wingspan is probably 5-7 mm.

They are commonly called "drain flies" because of their habit of laying eggs in the organic buildup inside drainpipes. You need to report these to maintenance as they are indicative of a sanitation drainage problem. They do not pose a hazard to humans or animals other than as an indicator of decayed organic material which can be a source of other organisms.

Thanks for the answer.

We recently had a problem with a moldy build up in the cupboard under the sink which got fixed, the flies appeared shortly after that.. I just checked the cupboard and it's full with adult speciments.

The caretaker will be back Tuesday, any idea how we can manage the pests until then?

Just about any flying insect spray should take care of them, or you can kill them with ammonia window cleaner, but you have to hit them with the liquid.