Hide questions under their seat and announce 'hot seat' sometime during the day. Whoever has a question under their seat has to answer it. Perfect way to review/have fun! This is an idea from kindergarten that could be used in ANY grade!!
"Homework Incentive" - When the entire class completes a homework assignment on time, hang up one flag. With the letters in "homework" and a starting and ending decorative flag, there are 10 flags in all. When the banner is complete, give the class extra recess, a homework pass, or whatever incentive works for your classroom.