NCAR's learning center is always worth an annual visit and is a popular field trip destination for school kids during the week. It's a good place to take visitors and it's free and open most days of the year. Water fountains and restrooms are there too which is handy for hikers.
The retired CRAY-1A that I mentioned last week. To find it, go all the way downstairs.
Looking at the Flatirons on a nice day. Taking the left here is the entry point to the trail system.