updated 6:49 p.m. ET Jan. 29, 2006

SALT LAKE CITY - The Arena Football League is undeniably quirky. And quite popular.

The AFL entered its 20th season this weekend, quite a milestone for something many wrote off as a fad when kicks first started bouncing off nets back into play, and football was stuffed inside basketball and hockey arenas.

The AFL is no longer a novelty. And as much as football fundamentalists may hate it, it’s not going away.

“Before, maybe one out of 10 knew what the AFL was. Now, maybe one out of 10 doesn’t know,” said David Baker, now in his 10th season as AFL commissioner.

From a fledgling four-team league that added some intrigue to the 1987 summer cable TV lineup, the AFL is at 18 teams with plans to grow; has a development league in smaller markets; and network television deals with NBC and Fox Sports Net.

Turns out adding a few twists to the old game was a hit.

While the USFL and ill-fated XFL couldn’t develop enough interest in football after the Super Bowl to survive, the indoor game has thrived. Cutting the field in half, collisions at the padded walls along the sideline, and the live-ball rebounds off the end zone nets make the game different enough to attract people inside to watch it.

“We are not a minor league of the NFL. It’s a different game with different skills and different types of players,” said Danny White, the former Dallas Cowboys quarterback and a veteran coach in the AFL.

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White is coaching the expansion Utah Blaze, the latest franchise to join the league that AFL founder Jim Foster thought of while watching an indoor soccer game at Madison Square Garden. Foster, who drew up his idea on a manila envelope he still has locked away in a safe, is one of the men who ran the league before Baker. He’s still part of the game as a partial-owner of the Quad City Steamwheelers, a member of af2, the development league that is at 23 teams and counting.

Foster said from the time the AFL debuted with the Washington Commandos playing the Pittsburgh Gladiators in the summer of 1987, it was clear the indoor game could be a hit.

“They didn’t come out going, ‘Wow I just saw an imitation of an NFL game.’ They came out saying ’Wow — that was something different,”’ Foster said.

It certainly is. It’s eight-on-eight instead of the standard 11-player teams. There is no punting and virtually no running the ball, leading to fast-paced games with plenty of scoring.

Just about anywhere on the field is within field goal range. And the trademark nets to each side of the goalposts are in play, so when the ball hits them and bounces back it can be returned, adding another quirk to the game.