Luvin Poker has a .NET site which features play-money-only gameplay. And, surprisingly enough for such a little-known site, their kiddie tables are actually some of the best around.
Beyond the standard No-Limit Holdem, play-money patrons will find Omaha, Omaha Hi/Lo, and 7-Card Stud. There are also Tournaments and Sit-N-Go's to be had. At least, that's what you'll think when you first check out their software. But, as it turns out, there are only usually tables open in the Holdem and Omaha tabs. A check of the Hi/Lo, Stud, and other areas yielded zero traffic, with no tables even open for play.
So, that's a problem. But, even if you can't find anything outside of Omaha and Holdem, you'll still be impressed with their available play money games. Early on a Thursday afternoon, there were 1,213 players online at 215 tables. That's not terrible for such a small site.
The games themselves move quickly, and sport a fairly wide range of limits. Because there are no tournaments available, you'll be stuck building your fantasy bankroll in the ring games. This will take time, and probably will lend itself to a more shove-based strategy. Since you can reload you chips if you fail to double up, there's no reason not try to instantly triple or quadruple your stack.
It shakes out like this – There are players here, and the games aren't bad. But the entire site feels somewhat like a ghost town, with a fairly bare-bones interface and empty “Today's Announcement” area. It's not a terrible play to play, especially if you're trying to escape the clutches of Full Tilt or PokerStars. But, because you'll be facing mostly shove-minded players, the skill level here is rather limited.