Lunchtime Power Hour

OK, Coaches (and swimmers), I've been swimming LCM at lunchtime a day or two a week, trying to supplement my ever-increasingly slacked-off summer evening workouts. Well, I am getting bored at making up things to do, but I'd still like to feel like I did something worthwhile before hauling back to the office. So who has some good ideas to share for a ~40-50 minute, ~1.5-2k lunchtime workout? I'll start... Last Friday, I did: LCM 400 fr w/u 200 bk build arms 2x200 snorkel 200 free good technique 8x75 {50 fly, 25 free}, ~20 sec rest 200 bk build arms to fast 300 {50 fast, 50 ez, 100 fast, 100 ez}