Off-hand, I can think of the following:
ICN - not in the lounge, but the airport has a great play area for small kids (slides, climbing structures, etc.)
MAD - ditto above, though even better, with separate adjoining spaces for toddlers and somewhat older kids (say 4-10 yo). In T1 A, I think, near the gates and the "Plaza Mayor" self-service restaurant.
BKK - THAI used to have a kids room in the main lounge, though I hear it's been discontinued
IST - the [old] Turkish Airlines lounge had a kids room, but it was pretty bare. Perhaps it has now improved, to match the rest of the swank new TK lounge?
ZRH - the airport itself has a fantastic room for families, especially for those with infants/toddlers. Lots of games, toys, books, as well as changing stations and sinks for washing out bottles and/or food containers.
Last edited by Michael; Nov 12, 2011 at 12:54 am
Reason: Update on ZRH, IST