Just doing a bit of self-advertising - desperate for a few sales!!!
I've just put one of those boiler lamps on eBay - the thing that spirals a tube of fluid upwards and appears to make it boil.
It here: http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=3304803929...
And it got me wondering if these boiler lamps can be classed as lava lamps or are they just far-flung relatives?