I'm with mrsg1, when we were TTC at first we just went with the whenever relaxed approach (knowing that ovulation was approx day 14) but after awhile not doing anything felt stressful for me, and actively taking control and trying new things actually made me feel more relaxed. I think I'll have to check out those monitors for next time, as didn't try that (oh dear, am I already thinking about next time?)
Anyway, the gadgets I found useful was charting, especially the charting thread. I liked OPKs and found them useful. I didn't like maybe baby as I could never get it to work. I used preseed the month we conceived so I liked that too
Not sure if you count acupuncture and herbs as gadgets, but I tried those and found that they helped regulate my cycles so I'd also recommend those.
I never tried the BD competitions but the competition definitely seemed to get a few of the girls (and their partners) inspired with some great results!