Even though she will celebrate her usual birthday extravaganza in Vegas this weekend at Marquee nightclub, Kim spent her actual 31st (today) doing something quite the opposite!! Hit the jump to find out what she did!

Wendy L.

The newlywed spent her birthday with sister Kourtney and nephew Mason at the Natural History Museum!! I know, shocking… but nothing is more fulfilling than the unconditional love of your family!

“Good morning dolls! Last day in New York! Off to Las Vegas tomorrow! Can’t wait!” she tweeted.

[source]