Do you know someone with a scalectrix or whatever they are called? (or play some other type of racing game on the computer) have a race, let him win, decorate a stool to look like a winners podium, cheap bottle of fizz to spray about everywhere (outside) and hand him the voucher in a gold envelope as his 'prize'.
Am very excited as have bought DH some tickets for the Grand Prix for his 40th, going to give it to him next Sat at a surprise party I have planned. I have a gift voucher printed off..so basically am going to give him a bit of paper as tickets not sent until closer to the time. Any ideas greatly appreciated how I could make it a little more imaginative.