How about, build a bed for Spiderboy!
Most of the cutting is done, and the frame is dry fitted.
What a mess.
Inspector Bittygirl is on the job.
Spiderboy admires our work.
Finally assembly begins.
Spiderboy makes the inaugural ladder climb.
Hey, I can touch the ceiling! Dad thinks, "hmmm".
"My God, It's full of stars!", or something like that. 
Spiderboy installs the Milky Way under the bed.
Let me just test this thing out here.
Ready to snore. Note Lego Spidey hanging from the ceiling.
