I say we give it until Monday for people to properly have a think at what they believe would work as a group experience, and then I'll add a poll to the topic. Why? BECAUSE IT'S MY GODDAMN TOPIC.
Ahem. Thank you DD64 for correlating all the info posted in the thread so far. .
Please, if anyone has a proper suggestion for this, try your best to sell it. Offer up potential checkpoints, a timespan for completion (something like Luigi's Mansion would run for two weeks at best, I reckon) and generally make us want to follow you like a cult leader.
The reasons why it should be Paper Mario have been stated before, but let me reiterate:
Easily checkpointed: We do a Star Spirit each week.
Not too long for each week: Each Star Spirit is at most about 5, slow hours of play. You can segment this up easily.
A feeling of adventure: Paper Mario is big enough for a sense of accomplishment. Luigi's Mansion will be over by week 2.
Easily Obtained: A few of the gamecube suggestions would be very tricky to get hold of, legally. Even illegally it's not perfect. Paper Mario is on the VC, and emulates very well (obviously only emulate it if you already own a copy).
On top of the fact it's actually a very good game, with great humour and battle systems, it's clearly the only choice.
Seeing as shamefully, Eternal Darkness doesn't seem to be gaining much traction, I will vote for Hitman: Blood Money, as it's a game where we can all regale each other with tales of how we tackled each level, being that there are so many ways to approach them and it would be very interesting to read different methods/strategies. Perfect for Playde.
Alpha Protocol: Banjo, Melatonin, Buffalo, final-fx  Broken Sword: bear  Brutal Legend: Dan.  Bulletstorm: Lagamorph  Crash Time: Frank  Darksiders: final-fx  Dragon Quest VIII: Sirus  Enslaved: final-fx  Eternal Darkness: Mockmaster, Mafro, PuppetBoy, Dalagonash  Final Fantasy VII: Parksey, Foxhound, Dark Dragon 64  Galleon: Dan.  Gears of War: final-fx  Ghost Trick: White Rabbit, final-fx  Giants: Citizen Kabuto: bear  Hitman BM: Banjo, smurphy, Herbi, White Rabbit, Anung, Dual, Mockmaster  Jak and Daxter: final-fx  Katawa Shoujo: Melatonin  Killer 7: Mafro, smurphy, Cuttooth, Dalagonash  Luigi's Mansion: Parksey, Frank, Banjo, Supachipz, White Rabbit, StayDead, PuppetBoy, the-elbo  Mass Effect: final-fx Pacman  Messiah: bear  Mystical Ninja Starring Goemon: Dan.  Ninja Blade: Anung  Outcast: bear  Paper Mario 64: aaronayl1, Parksey, Pacman, SchminkyPinky, Coconut Bob, Dark Dragon 64, Herbi, Count Nood, Wiggles, final-fx, addsy0  Pokémon: Dr. ogue Tomato  Prince of Persia: Two Thrones: Harry Bizzle  Psychonauts: Cuttooth, Winkle, OldSoulCyborg, Pacman, Delusibeta, Parksey, Harry Bizzle  Quake III Arena (PS2): Dual  REMake: Parksey  Robot: Rocket on Wheels: Frank, Dan.  Rollercoaster Tycoon: Banjo, Pacman  Skyrim: 1cmanny1  Sly Cooper: final-fx  SSX 3: White Rabbit  The Last Window: White Rabbit  Theme Hospital: Dark Ritual, Dark Dragon 64, PuppetBoy, StayDead  Thief 2: bear  Timesplitters 2: Dual, Wiggles, Banjo, PuppetBoy  Tomb Raider: Underworld: Harry Bizzle  XIII: Dan., Dark Dragon 64