Since 1999, SourceForge has the 'go to place' for all open source downloads, but in the last couple of years, Google Code has put up a bit of challenge. Remember also for a while there was this constant thread in media about how SourceForge had 100,000 project, though most had been abandoned. SourceForge.net now has 230,000 projects and if downloads are an indication, they seem to be doing just fine.