This park has a big lake where you can rent a battery or pedal boat for 1 hour. You see a lot of local doing all kinds of activities e.g. dancing, singing, foot badminton etc. Must see in the park is the 9 dragon screen and the white dagoba.

if you are in the area -- bus #5 goes past the Behai east entrance on its route between the Drum Tower and the Forbidden City. The west entrance to Jingshan Park is right across the street from the Behai bus stop too. Behai has nice views and interesting temples on a hilltop -- much stair climbing but worth it on a clear day. The cheaper ticket (no temple access) for the lake and park only is good for people watching.

After seeing how crowded Beijing is, I was very surprised to find such a vast outdoor space near the centre. We came out the back of the Forbidden City, turned left, walked for a short while, across the road and into the park. Definitely worth combining the 2 sights together in one trip.
Entrance is 20yuan per person but definitely worth it if you explore all there is to offer.
We went over to the island and climbed the hill first, then off the island over to the right and round the rest of the park. The gardens are well maintained, the paths are nice and wide and there are plenty of refreshment stands and toilets along the way. I can imagine in summer when the flowers are out it must be beautiful.
Unfortunately we were here when it was raining, otherwise it may have even got 5 stars in the sun! It's a lovely place to stroll and take time out of the busy city.

By the lake, a little pricey great for summer but cold in winter,
the lake is partially frozen! very touristy
The bars are ok with some being too touristy but good for a walk around, boat ride bbq or listen to a band.