Smallest linux distro

I'm looking to see if running linux will help me with running the BBC climate change BOINC program any faster. It's a machine with only limited resources (celeron 1.7 with 512 meg of 266 ram. - very low whetstone/drhystone benchmarks compared with my athlon xp 2400 (which runs at the same speed, just proving the already known - speed isn't everything).

Sooo, can anybody tell me what the smallest/lightest linux distro is (with a basic GUI obviously), using a kernel of late 2.4 or above?

Any Linux distro will run OK on that machine, so no need to go scrambling for extra lightweight stuff.

When installing, leave out Gnome and KDE and choose some lightweight window manager instead.

thanks Nodsu. In the end I installed Knoppix to the hard drive - purely because I had it lying around.