Grundig's GUPSW5000 wireless splashproof speaker...
If you can get over this product's truly awful looks, it could be a handy addition to your arsenal of garden goodies.
It is a wireless surround-sound outdoor speaker that is splashproof, which, rather than meaning it's waterproof, should give you just enough leeway to get it back indoors if it start to rain.
It boasts 20 watts RMS of sound, which should be adequate for music for a barbecue (it has an in-built light designed for use in the dark) and more than adequate for sounds to accompany solo sunbathing and has a decent 50 metre broadcast range.
Grundig claims it is simple to use, with no need for tuning. You just need to attach the transmitter to any hi-fi system, MP3 Player or other device with a line out cable and it will start pumping out your tunes.
Power can either be supplied via an AC adapter into the mains, or if you wanted to use it truly wirelessly then from eight D batteries.
Available on the Tesco Direct website - current price showing as £150.