doit
Sparc stable. It starts up as it should and keeps running. I don't know how long it takes to update the live statistics on the web site, however, so I can't tell if it's actually recording information about my system or not. The kernel that should show up is: 2.6.25-gentoo-r7-SB1000-dirty (From this system --- Linux polylepis 2.6.25-gentoo-r7-SB1000-dirty #2 SMP Sat Sep 13 14:23:59 UTC 2008 sparc64 sun4u TI UltraSparc III (Cheetah) GNU/Linux which is an asymmetric multiprocessor (1x750, 1x900)
For those who care, if any, the kernel on sparc did show up for me.
ppc stable
x86 stable
amd64 stable
Stable on alpha.