Sometimes being a stoopid man and buying her flowers and undies/chocs etc because you can't think of anything else is actually the better idea.
What we see as a cool, whacky gift idea usually goes down like a lead balloon ~ particularly if it turns out to be something we want to play with.
The laydees want something a little more romantic than something to tone their muscles. Even if she is into keep fit she doesn't want her nearest and dearest saying, in effect, you are getting flabby, here's a nice exercise device I've bought you and LOOK I can do it too.
