Something is draining my battery?!
 

I have a 1997 C230 with about 122 000Km that I bought used four months ago and a new MB battery was installed at that time. Last week I noticed that the engine didn't turn over with as much punch as usual and sure enough, a few days ago it wouldn't start the car. When I'd turn the key, I just heard a series of clicking noises. I then boosted the battery (after reading some of the posting, I now know this isn't a great idea), started the car, drove for a while and the battery was charged enough to start the car. However, when left overnight, the same problem was present the next morning.
Anyone know of any electrical problems which could be draining the battery when the car is left sitting?

Appreciative of any input. :D

1997 C230 122 000Km

Measure the current draw on the battery and then pull the fuses one by one, when the current drain stops, you have found the circuit that is pulling the juice.

With my bimmer, I found that the trunk light was not turning off when the trunk was closed, thus with the car sitting for extended periods of time and the 5 watt bulb burning for days, it would eventutally run down the battery.

Fixed
 

Just spoke to the shop here I bought this benz and they've isolated the problem... human error. Turns out a new battery was never installed in this car, although it should have been, and it just died. It's replaced and they've picked up the tab.

PS, thanks for the previous replies.