This is an absolute classic, up there with a Wheelybug and Lego for brilliant toys that YOU SHOULD HAVE! Endless entertainment, and no mess! You get a big fabric sheet to draw on, with colourful alphabet surround, plus 2 pens to fill with tapwater. Ours also came with some stencils which were completely ignored by the children.
Both my 19 month old daughter and 6 year old son love this, and play happily together. We take it on all trips, as it folds up into my handbag or baby changing bag, and has been used under restaurant tables, in hospital waiting rooms, and practically everywhere else. You can use it on the fussiest granny's carpet - 'cause it's only water!! genius!
I's also recommedn a selection of the mini-mats. Much more limited play value - you're really just 'revealing' the hidden picture rather than being creative - but a worthwhile addition to anyone's child-entertainment collection especially for trips out to restaurants etc.
I personally think the Classic mat is better than the Thomas and Disney Princess versions; they immediately limit the interest and come with easily-broken and rather gimmicky accessories.