Only Sega Mega Drive. I'd have some kind of tournament which would go like so:

All Participants - Toejam and Earl-a-thon
You get points by - Number of ship pieces, enemies killed, opening random presents and not getting Total Bummer. Half the participants will be knocked out in this round.

2nd Round - Sonic 2
Remaining participants will take part in a timed challenge of beating Emerald Hill Zone 1 and 2. Half the participants with the worst times will be knocked out.

3rd Round - Streets of Rage 2
Points based again. Get points on the number of enemies beaten. Lose points with friendly fire.

Semi-Finals - Jungle Strike
Points on not blowing up DC or the President, points given for number of people saved and time taken.

Finals - Sega Mega Collection 1
First round is Super Hang on, best times stay on. Then remaining participants are randomly paired off in matches of World Cup 90. The last players will play Columns until a Sega Master is crowned.

Medals will be given out by the only games master, Patrick Moore. /bull$#@!