Indeed I do. Get a jump rope (and as a lady, a good sports bra to go with it). This, and once you've got the hang of it, jumping the rope is actually FUN, especially with some kickin' tunes filling your ears.
If you're game, the absolute best cardio training I've ever had has been with lumps of iron called "kettlebells" (I can already feel Lori's eyes rolling wetly up in their sockets). I'm turning this reply into something only slightly shorter than
Jane's History of the Slingshot (Vol. II), so I will leave you with this--
www.russiankettlebells.com .