Ask HN: How does a hacker have maximum fun with 500 euros?

Recently I recieved an email from my boss that I'm about to receive a gift of 500€ ~= $675 (and no he doesn't work for our nigerian branch ;)). The thing is that because of taxation reasons it needs to be spent somehow and I just can't take the cash and save it for something. Most people have taken gift cards to subvent their spending on TVs, holidays, etc. I've been traveling more than enough during the last 12 months (I've spent about 3 months at home) and I don't want/need a TV or a set of speakers.

So my question to you good people of HN is: what should I do with the money to have some hacker fun? Ideally I would of course want to spend the whole 500€ (it probably can be several items but a single purchase).

I like building / hacking things, I like hobby electronics and I don't want an iPad.