Seriously, get yourself down to Port Lympne Animal Park in Kent
It's about fifteen quid a ticket if you book online, unfortunately sprogs don't go free I'm afraid which is probably the only downside I was there this weekend reviewing Hevy Festival (shameless post in the music forum yet to come) which came with free entry to the park and while usually I'm not one for zoo's and safari parks it was a brilliant afternoon out!
BIG enclosures filled with everything from Black Rhino's to Silverbacks and Snow Leopards that you could actually walk around, instead of being ferried about in a car and seeing them from a distance for a few minutes at a time you could take your time, like we did and get as close as the fences will allow, we wandered around for nearly four hours and we saw maybe half of what was there having to leave the stately home, gardens and safari tour featuring wolves, tigers, elephants etc etc to get back to work.
Great staff, animal lectures, a scavenger hunt type stamp system on all the exhibits for the kids and even a couple of places where weary parents can sit down and grab a (reasonably priced) beer or two with some BBQ, usually I find myself wanting to be back and watching the bands a few days after a festival but honestly I'd quite happily go back and check out the baby Rhino and African Hunting Dogs again instead