I gave my six year old this party and it was such a big hit. It helps to know a local contractor if you want to go elaborate with the celebration(although the simple ideas were a big hit too.) I printed out the invitations on our computer using construction graphics and announced "WE WILL BE BREAKING GROUND ON MAY 15 1999. YOU AND YOUR FAMILY CREW ARE INVITED TO ATTEND" ETC... We used "caution" tape to decorate and seal off areas that were off limits to the children. I cut out "stop" signs, "road work ahead" etc. with poster board and placed them around the party zone. The table cloths were old blueprints and I used my sons remote construction vehicles for the centerpieces. We played a relay race game using safety goggles, toolbelts, levis, workboots and gloves. The children divided up into teams and each time they ran across to their teammate they had to dress the other "for work". The last child on the team to finish dressing for work wins! Another fun game was wheelbarrow races. We used plastic children's wheelbarrows filled with small rocks.  The first team to cross the finish line wins. The last game we played was "Who can build the highest skyscraper". Given a certain amount of time the children used legos to build their masterpieces. The highlight of the birthday party was a scissorlift parked in our front yard which my husband and the birthday boy lifted each partygoer up to the sky to wave to the others in the backyard(We had parents ok before boarding each child)Each child received a plastic hard hat(found at a local party store) with their name printed on it. They all were awarded a prize for participating in the games so we didn't have any hurt feelings. I took pictures of the children in their hard hats while on the scissorlift and sent them to each child in the thank you note. With all the repeat parties the kids had been to, this was by for the most unique.