My son's 2nd birthday was a construction party. We bought the packaged plates, cups, napkins, etc. which gave lots of time to spend on creative touches for the party.
We decorated the backyard using some road construction horses w/lights that flashed and tons of orange cones. These were rented at a construction place for about 15 dollars. We then bought yellow "Caution: Men at Work" tape, a HUGE roll for 1.50 at a local hardware store. My husband pulled ladders, etc. out of the garage and anything you don't want played on/with you just wrap in yellow tape. We lined our outside fence w/the tape and haphazardly strung it around chairs, across doorways, etc. Food: We made brownies and chunked them up messily and served them in the bed of a newly bought toy dump truck to look like boulders of dirt. I put a construction sticker on brown paper bags and made each child a sack lunch: sandwich, chips, and apple. I put all the sacks in a big emptied out tool box. For drinks, we borrowed an industrial yellow cooler from McDonald's(they require a deposit-10. but it's returned. We put the tub of ice cream inside a new bucket and served it with a shovel. We dressed our kids in denim overalls and construction boots and bought plastic hard hats for all kids. Home Depot gave us some nail aprons which were great for mom and dad to carry around wipes, camera, etc. A friend gave me the idea to get a truckload of sand delivered during the party. The kids could watch the dump truck and then they played in the sand pile with buckets, shovels, etc. You can then use the sand to level your yard. We borrowed a bulldozer sand box from a friend for the little ones to sit in. We also put out all the blocks and trucks and bulldozers we had for them to build and play with. I got two refrigerator boxes, cut holes for door and windows and let the kids "paint the house" and decorate it. Party favors were a bottle of bubble bath (dollar store) with a poem I made up and printed on cute paper and attached w/yellow curling ribbon that said: "A construction worker's day is tons of fun, And now your work here is all done. You did a great job, now you deserve a treat. A bubble bath just can't be beat! Construction worker gets dirty you see, Now fill the tub, relax, and have a bubble bath on me! Love, Foreman Josh" Invitations read: "Foreman Josh is turning two, Which means there's lots of work to do. The party's at Carter construction site, Saturday, April 3rd will be dynamite. Your shift begins at eleven and lasts until one, You'll probably get messy, so come dressed for fun! This was so much fun and Josh is still talking about it a year later!