They are all tasteful and witty, but naturally I went for this one:
I ordered it on Monday evening and it turned up yesterday. It's a lovely, soft, comfy T-shirt, the fit is good, the design is positioned so that none of it is hidden when I tuck it into my jeans, and it arrived in a packet sealed with a UNIT sticker, accompanied by a postcard depicting a blueprint of the Whomobile. Now that is service.
Nobody at work has commented on it yet :(