To add a little fun to your work out try the Card Game! It is a way to mix up your workout...keep yourself on your toes...and get a continuous 20 min workout!
Use a deck of cards...assign a workout to each suit. For example:
Crunches - hearts
Bicep curls - spades
Push Ups - Diamonds
UpRight Rows - Clubs
Then one by one flip each card to reveal your next workout. The number on the card represents the number of reps you will do. So if the first card you flip is a 2 of hearts, you will do 2 crunches. Do this until you have gone through the entire deck. It should take you about 20 mins!!