Recently R's parents came to visit and we had a great time taking them around to different places. A nearby must see was Teratak Perpatih or The State Museum of Negeri Sembilan. We visited just after a rainstorm so it wasn't too hot out in the mid-afternoon and the sun was covered with clouds (somewhat of a rarity around here in the afternoon!).
I wrote about the State Museum in my "Places to Visit and Eat in Seremban and Negeri Sembilan" post awhile back here. What's great is that the museum is located right here in Seremban just off E2 at the main Seremban Exit 218 (you drive towards town and you will see the brown buildings on your right. Do a U turn at the Specialist Hospital turn and go back to the entrance).
Alright, the museum is a bit lacking, but you can go in these traditional houses which is pretty cool and worth the trip.