As several people have already noted, the ulockable mp map in Halo 2 bears a strong resemblence to the M2 classic, Thunderdome. It seems another Marathon map has made its way into Halo 2, if Evil Otto (as quoted by mnemesis) is to be believed. From a fourm post on HBO: "Evil Otto is amazed that his egg on Turf hasn't been noticed yet. He also noted that Gemini began life as an almost direct copy of a Marathon multiplayer map." (Link: http://carnage.bungie.org/haloforum/halo.forum.pl?read=608137 )
So the question is: which map is it? Could it be the long rumored appearance of Mars Needs Women in Halo 2? The official Bungie word on Gemini (from Frankie's 'What'sUpDate') is as follows: "Gemini is a deceptively big and mostly indoor level set on High Charity. The Covenant environment is dark and foreboding, and the twisty corridors and teleporters make it a tough level to navigate when you're pursuing a flag carrier, for example. Learning shortcuts here is key to success, and note the location of the enormous Prophet statue…" This sounds like it could describe any number of classic Marathon maps.
A video of the level was leaked a few weeks back; I found the following link to the video on the Halo Planet forums:
http://flame-tide.com/halo2_new_maps_ft.WMV
From the video, I couldn't tell which marathon map inspired the new halo 2 creation - maybe you guys will have better luck?
-Kraken
