Procrastinating aged nerds of the world, unite! After literally minutes scouring the literal powerhouse of computing excellence that literally is comp.sys.sinclair (current hot topic - "Why do Spectrum users have tapeworms?"), I have found a challenge worthy of the best of you.
I speak of none other than the ZX81 Graphic Competition 2007. Challenging indeed, given that the mighty ZX81 has a graphics resolution of 64x48 pixels, each of which can be either on or off - I'm sure I've used fonts where the full stop was higher resolution than that. Furthermore, it's not just a matter of doodling your meisterwork on a piece of graph paper: you have to write a program that draws it.
"But I'm not one of those blessed with a genuine working ZX81!" , you may say. Off to eBay with you, scamp: there's no excuse for that state of affairs these days. But while you're waiting the competition website has links to a selection of emulators, so you can get cracking the while - and there is a certain pleasure in making your quad-core 2GHz megamachine pretend to be a Z80 running at 3.54MHz in a 1K sea of memory.
Don't just sit there like a BBC Micro user! Get cracking!