For my daughter's 6th birthday, she wanted a construction party. The only decorations I could find were yellow plastic hard hats and plates/napkins with this theme.  Each child received a tool pouch apron and small tools (we bought an inexpensive set of several screwdrivers and divided them), carpenter's pencil, rulers, etc.  My brother gave her a remote control construction crane which we used as the centerpiece.  Instead of a cake, we had cupcakes, which we speared across the bottom with a bamboo skewer in order to hang from the crane.  Each child took a turn dumping the freshly frosted cupcakes into paper plates of various types of colored and flavored sprinkles. Even the adults wanted to take a turn.  We had to send home extra cupcakes for each sibling so everyone (parents included) could have more turns at this game. The pin-the-girder-on-the-crane game was a hit. I drew a picture of the big yellow crane (with a piece missing) on poster board.  The pieces were personalized Popsicle sticks.  We read Mike Mulligan's steam shovel during the quiet time of the party.  The kids built buildings with construction paper shapes (pre-cut) which they glued to old shoe boxes.  They all loved this and got to take them home. My brother gave me a great idea for decorations - I bought some yellow and black caution tape at the hardware store (the type like you see at crime scenes or blocking manholes). I used it instead of streamers (one roll goes on forever) and made large bows out of it to hang on the front porch.  I used gold and silver metallic curling ribbon to hang tiny metal tools (Cool Tools) from the chandelier - they tinkled and sparkled.