In the past, my missus has rented a treadmill, and a dinky home gym that I outgrew in 6 weeks. Also:
Billy Brag home exercise dvds - hardly used
A Wii Fit - gathering dust
Currently owns a cross-trainer, which she has used once this month, and that's the first time in a long time. I bought it for her last June as an early birthday present she asked for specifically.
There's more but I can't recall it just now.