Bought as a Xmas stocking filler for our 8yr old daughter, this has proven to be a surprising hit. So much so that two of her her friends have pestered their parents to buy one.
You do need to provide some red food dye, veg oil and bottled mineral water but all that is easy to obtain and well worth it. Bubbling volcano ( ok, a reaction causing bubbles to rise within the volcano shaped mould, eventually overflowing at the top) , crystals forming within hours on a cardboard tree were both highlights but the greatest excitement was bringIng the,ahem, swamp monsters to life. Not as bad as it sounds, basically some form of micro shrimp but you can keep them alive and each them grow.
Been going for two weeks now and the interest remains. Highly recommended. Your life is empty unless you have to check your swamp monsters every night!