Day out required in london for birthday suprise..

Right, it is my boyfriends 42ed birthday in one week - more like 22 than 42... I need to plan something in london for him that does not cost that much money. He has money coming out of his ears and I am skint. What can I do that is really fun,...

interactive, thoughful and imaginative. I can spend about £100... And want a gigantic laugh!

Please help me! Much love

Emma x

Have you ever gone geocaching? I just started doing it not too long ago, and it's definitely all of the above. Best of all, once you get a cheap GPS, it's completely free.

How it works is this: all around the world (and London too; I just checked), people hide little boxes, bags, or other small containers and post the longitude and latitude coordinates of its location on a geocaching website. You plug the coordinates into your GPS and try and locate them. When you find them, there's usually a log to sign and sometimes some trinkets to exchange for some of yours.

What's great about it is that the GPS will only get you to within 10 or 15 feet of the final location, and then you all have to work together to try and figure out where someone might have hidden the treasure. It's a never-ending scavenger hunt that it takes you to a lot of very interesting places as you try to hunt them all down.

My GPS cost me about $80 US, and my girlfriend and I head out all the time to try and track down the trinkets scattered around NYC (and once in Washington DC).