Got this linked to the source...I think :)
My Favorite FREE 1st grade math centers!
Learning Adventures with Mrs. Gerlach: Math B.U.I.L.D. Centers with Freebies!
Math Daily 5 (BUILD) B=Buddy Games, U=Using Manipulatives, I=Independent Working/Reading, L=Learning About Numbers, D=Doing Math
Build your Rocket free printable.. maybe adapt for building/construction theme with buildings instead of rockets
math centers based on B.U.I.L.D. (Kickin' it in Kindergarten)
Counting on from any number math stations, worksheets, and activities that are super fun - Building Number Sense in First Grade
Teaching resources and ideas
Miss Van Maren's Fantastic First Grade: BUILD Math Rotations
2D Geometry and dabbling with Inquiry based teaching - using geoboards to explore shapes and engage kids.
2d and 3d shapes
Magnet fishing - this could put some life back into the magnet center!