I don't know about these days, but when I was a kid the local council used to organise "torchlight adventures" for kids in the school holidays.
You went up the hills, along the beach, eeling, fishing, playing games, etc, after dark. It was great!
If you've got kids in tow, it would be worth checking with the Kapiti District Council for what's happening in the holiday programme (runs for most of summer).
Paekakariki is a very small place. You could go to the pub (which has live bands on the weekend), or to the cafe or one of the restaurants, but to get the true Paekakariki experience I recommend heading down the beach, collecting up some driftwood, and getting yourself a bonfire going (legally needs to be below the high tide mark).
Or even just take a bottle of wine/few beers/your fish and chips and just sit on the beach and watch the sunset!