One of my New Year's resolutions this year was to get abs, and Jillian Michaels' "6 Week Six Pack Level 1" got the job done! The video uses one dumbbell (5-7 pounds) and is just over 30 minutes long. Although it's goal is to get results for your midsection, the video is actually pretty comprehensive incorporating lower back strength exercises, along with abs. Another thing the video does that is signature to Jillian is using HIT training-high intensity training, so the video incorporates 30 second cardio intervals like burpees and mountain climbers that get your heart rate going and the fat burning!
Following 6 Week Six Pack I completed Jillian's "Shredded in 30-Level 2." The Shredded in 30 series has 3 levels, all of which are great 20 minute workouts. Each uses a set of dumbbells. Warning, level 1 seriously works your soldiers like nothing else!
Try these two out, I think you'll really like them and they are, especially, great if you have limited time to workout one day!