My son is infatuated with LEGOS. So, having a LEGO party for his 5th birthday seemed a no-brainer.  For INVITATIONS: I used primary colored (red, blue, yellow, and green) blank cards (found at a craft store). I punched out 6 circles for each card in the same color as the card. I then attached them on the front of the card w/sticky dots" to look like an acutal LEGO. It gave the card a 3-D look. I also wrote LEGO on all the circles. On the inside of the card I put all the normal information we're going to have a great time celebrating Max's 5th birthday".  DECORATIONS: I purchased some Duplo party decorations on-line. They don't have LEGO but my son loved them just the same. I only bought the cake plates goodie boxes large napkins and pull-string pinita. I filled in with primary colored plastic ware cups and small napkins.  I made what I called abstrac LEGO art. I took foam core board in my colors and cut it in to large squares and rectangels. I took a glass (used like a stamp) and with paint in the same color as the board put circles on the shapes to look like a LEGO.  I put them around the room. I also had lots of balloons table covers and streamers in the same colors. I wanted it to be very bright and colorful...and it was.  ACTIVITIES: Like other entries have mentioned we did a LEGO building contest.  I had enough awards (made on the computer) for each child so every one won (ie. Most Creative Tallest Most Colorful etc..).  I took picutres of each child with their creation.  I will include a copy of the picture in their thank you.  We guessed how many LEGOS were in a container.  And we had the pull-string pinita (filled with lots of LEGO gummies and other bright colored candy). FOOD: I kept the food simple just corn dogs pizza and homemade mac-n-cheese.  Side dishes were green salad friut baby carrots and chips. On the tables I had M&M's but I took out the brown ones so they kept with the theme.  CAKE: I made two 8" square cakes.  I frosted one in blue and one in yellow (my son's request) and stacked them on top of each other.  I tried to use the upside down cupcakes for the "bumps" but it just wouldn't work. They crumbled and fell apart as I tried to frost them.  I ended up using large marshmellows cut in half.  It worked out great!!  I also made cupcakes. I frosted them with white frostingand then put LEGO shaped choclates on them.  I used the LEGO ice cube tray (found at the LEGO store) to make the chocolates.  I made them of course in the primary colors.  People thought they were real LEGOS.  FAVORS:  I will admit I go a little crazy when it comes to goodie bags.  I kept everything in my colors.  I made glycerin soaps shaped like LEGOS.  I used the cake/gelitan mold (found at the LEGO store or on-line). I included some of the chocolates that I had made. I also made LEGO key chains.  We bought LEGOS from the bulk bins at our local LEGO store. We drilled holes in the top screwed in a eye screw added some chain and topped it with a key chain ring (all found at a craft store by the jewelry stuff). I also included non-homemade items: packs of LEGOs to put together (they were on clearance for $10 after Christmas. It's a box w/9 different "classic" sets. I've seen them now and they are $20...they worked perfect for goodie bags) bubbles LEGO gummies and a bouncy ball. That goodie bag was packed!  Every one had a great time even the girls...and adults.  "