This Month's edition of the Cartridge Club is good old Halo: Combat evolved. If you have a copy of Halo, dust it off and go get signed up for the Cartridge Club forums.
I have several of the Halo games, but I don't think I have a copy of the original. I'll have to get on eBay and fix before the end of the month so I can get in on the discussion a bit.
Check out the Cartridge Club here.
Check out this months game topic on their forums.