There are a lot of useful things you can do in your pool, and kudos to you for wanting to stay active during your enforced surface interval.
Polishing buoyancy and trim is one useful thing. Play with your weights and the positioning of them, until you can float in a horizontal position without finning. You can easily construct a buoyancy course, as has already been mentioned, using hula hoops and dive weights and different lengths of cord, and learn to swim through hoops at different depths by breath control alone. If you can contrive a weight with a stick sticking up from it, you can practice hovering with one fingertip touching the stick, and then with your nose touching it (much harder!)
Once you are rock solid at buoyancy, add task loading. Try flooding and clearing your mask in midwater, without changing depth or swimming yourself out of position. Do regulator recovery the same way, and then practice air-sharing with your wife, trying to hold your position in midwater while establishing the air-share, and then doing a controlled, slow ascent.
Practice swimming with no mask or with your eyes closed. It really keys you in on the physical clues for depth and orientation in the water.
Learn the alternative kicks -- videos of frog kick, back kick and helicopter turns are available on YouTube.
Lots of stuff you can do in a pool.
