Going to the park is always fun and my kids love it.
And the great thing about going to the park is that its free. There is always parks for kids to play at- wherever you are. My kids love going to the park and the one near my old workplace (by the sea) is always a favourite - especailly as the park has had a renovation and has now a pirate ship as part of the play area.
When we are on holiday, we always have to find the nearby park - anything to get rid of energy levels.
Sometimes, we meet friends at the park and have a picnic, always fun and a cheap day out too.