Madden NFL 07

If for some reason you have 30 years of franchise, but have yet to reach level 50, there is a trick to getting a boatload with relatively little effort. (My profile got corrupted, so I never got to 50 the first time)

Start a franchise with all 32 teams, and sim up to week 15. Save the franchise. Now sim through the Super Bowl. You will get a ton of progress, like 4-5 levels during this 7 week period. I think it has something to do with clinching a playoff spot, and also winning playoff games. I'm not sure, but it doesn't matter.

When you finish the Super Bowl, re-load the franchise and start from week 15 again. It took me about 10 tries and 15 minutes to get from level 18 to 50.

Select all teams under franchise and then sim for 30 years. You will get Madden Gamer Level 50 and 30 years of simming around the same time.

Just an addition to previous solutions:

I'm not sure if it's just happening to me, but I recommend simming until you get to level 50 in ONE sitting. Every time I save the game, exit, and start the game up again my gamer level is back to one. It would be a shame to do it so long just to have it reset.