Not really. DHT and peer exchange can be used without a tracker. Here's a PHP script to create non-private-flagged version of a pre-existing UG torrent: http://pastebin.com/nmjPYspe Here's an online version: http://www.underground-gamer.us.to/converter/
Unfortunately nothing so far. At the present it's in a limbo: the possibility to revive the site is certainly there, but it all hinges on the owner's decision. Anyone's guess as to what that will be and when he will make it.
The least they could do is put the site up for a couple of weeks so people can finish up unfinished business....I have about 4 or 5 torrents of dev stuff there that I've been meaning to re-download as I lost my local versions in a hard drive crash...but I guess I went and waited too long :/
Gentlemen. There is news. You might want to take a valium or two. As of now, I have confirmation that UG is not coming back, period. There was a miscommunication - the owner never intended to reopen it in the first place. All I had was the knowledge there exist theoretical means to bring the site back and a lack of a definite "not coming back" from the owner. So I guess I'm at least partially at fault for this misunderstanding. Sorry for making you hope, guys. It's been a fun ride.
Not happening. This isn't "the least" but rather "the dumbest, most suicidal thing" we could do at this point. Go to the IRC channel, sign up on the temp forums. There are tools available to process UG torrents and create non-private-flagged (ie: trackerless) versions.
Ouch, that hurts for all the great games collection projects that were initiated on UG. I did download the v1 PSX NTSC-US game collection so I could put it on seed when another similar tracker would take UG's place.