Some fast food restaurants (McDonald's, Carl's Jr., Burger King, etc)
have large play structures for kids to climb around in -- usually a
maze of interconnected tubes and slides, going up to around 10 or 12
feet high. I'm looking for such play structures in the San Francisco
bay area -- specifically, on the peninsula, near San Mateo. I know of
one, in the Chuck E. Cheese's in Redwood City. I'd like a list of
other ones (name of fast food restaurant and location) within a 10
mile radius of San Mateo, CA.

All the fast food places have "locator" web sites where you can plug
in a city name, and get a list of all the restaurants in the area. 
However, only McDonald's seems clever enough to include information on
play areas.  Since they have the best paly areas anyway (my two young
boys are experts on the subject) might as well stick with them. 
Here's a list of all the McDonalds playlands within 10 (actually, 11)
miles of San Mateo:

http://www.vicinity.com/mcdonalds/

MCDONALDS

522 EL CAMINO REAL
BELMONT, CA 94002-2121 

185 CHESTNUT ST
REDWOOD CITY, CA 94063-2105 

201 TANFORAN PARK MALL
SAN BRUNO, CA 94066-1302 

405 A SOUTH AIRPORT BLVD
SOUTH SAN FRANCISCO, CA 94080-4402 

190 STANFORD SHOPPING CENTER
PALO ALTO, CA 94303

Great answer, and super-duper prompt (18 minutes after I posted my
question). Thanks!

Here are the Burger Kings in the area, not sure about play places:

 1. Burger King 3586
1453 Burlingame Avenue 
Burlingame, CA 94010 US 
Phone: (650) 340-8905 
Distance: 1.66 miles from the center
 
 2. Burger King 3323
2817 South El Camino Real 
San Mateo, CA 94403 US 
Phone: (650) 341-7400 
Distance: 1.92 miles from the center
 
 3. Burger King 11002
44 Hillsdale Mall, Space #6078 
San Mateo, CA 94403 US 
Phone: (650) 312-8484 
Distance: 2.15 miles from the center
 
 4. Burger King 2044
420 El Camino Real 
Millbrae, CA 94030 US 
Phone: (650) 697-5866 
Distance: 4.59 miles from the center
 
 5. Burger King 10442
505 Skyway Road 
San Carlos, CA 94070 US 
Phone: (650) 596-5610 
Distance: 5.06 miles from the center

Fair warning on that McDonald's address on South Airport Drive --
there is no play structure there. The McDonald's Web site is just
plain wrong. Plus, the Stanford Shopping Center play area recently was
remodeled drastically to add eating space for general customers and
eliminate play space for kids. It's no longer worth the trip. Also,
keep in mind that most play areas close an hour or more before the
fast food joint does so that the cleaning personnel can get in there.
When my four-year-old and I went to the one at Tanforan to play, I
made him eat his dinner first (as I always do). When he finished and
ran to the play area for his "reward," a manager kicked him out
because personnel were in there cleaning. Only after my son burst into
wailing tears and I became enraged did the manager allow him to play
for all of 10 minutes. We won't be going back there. I'd suggest you
focus your play efforts at the McDonald's in Belmont. It's big,
friendly and reasonably clean (most of the time). By the way, have you
taken your kids to the water play area at Stafford Park in Redwood
City? Take swimsuits, towels and water shoes, if you have them, and
prepare to watch the grand fun.

Oh, and there's also a Chuck E. Cheese hidden away behind a Red Robin
(I think) just north of Tanforan. Drive around persistently enough in
that strip mall area and you'll find it. My son prefers the Redwood
City one, but I have no idea why. He seems to think the games at the
one near Tanforan are out-of-order more frequently than the ones in
Redwood City, but that hasn't been my experience.