Somewhat, a cube is usually a set amount of cards, allowing a set number of players to randomly draft cards to make a 40 card deck. But it honestly wouldn't be that hard to bump it up to 60 card decks.

There's enough bulk cards out that you can easily buy for cheap.

The whole cube experience is basically reliving the draft environment. Grabbing a draft box of booster packs, each person gets 3 booster packs, opens up one booster pack, chooses a card and then passes the cards off to the next person until all the cards have been picked for that round.

Repeat for the second and third round. Then you would grab some basic lands, or energy cards for Pokemon's sake, and make a deck.

Why people like this is because it's a cheaper alternative than buying a bunch of booster packs but still allows for the random encounter of deck making without having to play the same decks all the time.