In the interests of researched blogs I tried this super-set routine today, (from American Council on Exercise) which works opposing muscle groups with each set. I went through this in just over 20 minutes, (not including warm up and cool down) making it an effective, time efficient routine. For each 45 seconds of exercise I completed approximately 20 repetitions, giving it a strength endurance emphasis, but you could reduce the timings to 30 seconds, if you wanted a purer strength session. Opposing muscle group super-sets allow you to fully fatigue one group of muscles, then do the same with the opposing set, before repeating the set.
It is really pleasant to go through a routine which someone else has thought up, for a refreshing change. The exercises use either a dumbbell set or band, and the equipment is interchangeable between some of the exercises. The only one I would improve on is the band lat pull, where it is preferable to attach the band to something stable above head height, (or behind your head if you are lying on the floor) to make it a truer lats exercise.
Happy resistance training!