General

You have melee. You don't need anything else.

TimeSplitters Future Perfect. (Prequels are good too).
Tom & Jerry War of the Whiskers is surprisingly fun too.
Mario Kart: Double Dash is decent.
Sonic Adventure 2: Battle (The multiplayer isn't the main selling point, but it can be fun)

Tom & Jerry war of whiskers "must play game"

SSB Melee.
Nicktoons Unite (Played this all the time with my friends)
Mario Kart Double Dash

Kirby air ride city trial mode. Will cure your boredom in seconds.

What heresy is this why isn't Mario Kartouble Dash on that list? Get it.

[quote=MagiBombchu]Mario Party 4
F-Zero GX(though you have to unlock a lot of stuff in the single player mode)
Tales of Symphonia
Final Fantasy:Crystal Chronicels (Assuming your friend has a GBA/SP and the proper cord to connect to the Gamecube)[/quote]
A good list. Also, Four Swords Adventures and TimeSplitters 2/3

Paper Mario and the Thousand Year Old Door
not multiplayer but it's such a foking good game

I love everyone on this thread lets all go to my house and play gamecube ihave candy <3 oh i miss Sonic adventuer battle 2, Super mario sunshine, Lugis mansion, Mario party, Meele, Mario kart,

[quote=yaytime]Melee is all you need.
or Mario Kart DD.
Warioware.[/quote]

This is basically what I played with my friends on my Gamecube.

Melee, hooves down.

Multiplates. Oh yess. More plates more food.

mario kart double dash, the only mario kart to have an ALL cup(forgot the name) where you race on all the stages in random order starting at luigi's level then randomizes the rest and end with rainbow road

Mario Kart Double Dash
Pokemon

Mario Part 4 is a fantastic game. Luigi's mansion was quite fun, as well. Custom Robo is also a great game that I'd suggest.

super smash bros melee is a must

Mario Party 7 with the Deluxe mode so you share a controller.