No, really. All you need to do is be really good at one of them. Like Halo 3, FIFA 10 or Madden 10. From Virgin Gaming:
Reserving your bracket spot is easy – from now until August 8th, the top 128 players on each game’s PS3 & Xbox 360 Virgin Gaming leaderboard will receive free entry into each game’s respective bracket. All of the brackets have prizes ranging from $6.25 (one win) to $875 (bracket winner). As always, these gaming tournaments are free to enter and open to members of all skill levels.
Sure, they’re open to members of all skill levels, but 99% of those members are leaving empty handed.
This isn’t going to make anyone rich, but if you’ve got the skill and experience, I say go for it.