Here's a game where you pit groups of students against each other.
Click on the picture above to get a full size sheet you can print out.
Print onto durable cardstock and cut out on dotted lines. Place the squares into baggies so that Team 1 gets the "A" group of letters, Team 2 gets the "I" group of letters, and so forth.
Have the children pick one person on the team to be the scribe.
When you say "Go!", each team dumps their letters on the table and starts moving them around to build words. The scribe writes down every word they make.
When time is up, the team with the most words wins!