My daughter (yes, daughter) is big into medieval knights and swords so we had a medieval theme. I got many of the ideas here (I love this site!) but thought I would share a few of my original ideas too.  I probably went a little farther than most because I sew and had scrap fabric. I made night tunics for all the kids. Blue ones with silver fleur de lies ironed on the front and burgundy ones with gold fleur de lies ironed on the front. I have a front porch with four posts so I hung medieval banners that I had made.  One with a fancy letter for our Last name.  One with a medieval looking lion.  One with a fleur de lies to match their costumes and one for the party girl - a fancy letter for her name and a horse (which she also likes).  Invitations were made on our computer with Old English style text and printed on parchment paper.  It read:  Lady (Sir if it was a boy)Lauren of Riley (the child's last name) Noble Knights and Ladies Fair are invited for feasting and festivities in honor of her royal highness - ERIN RILEY.  We then rolled them up and tied a thin ribbon around them like a scroll. We had to hand deliver them but everyone lived close. We also mention that they were encouraged to wear any appropriate costumes.  Several girls took the opportunity to wear the princess dresses.   When they arrived we handed out the different colored tunics for each team.  King Richard (my husband Rick) told them he needed more taxes to build his castle and they need to "collect taxes". I had hidden chocolate coins (which I refrigerated but suggest the freezer) all over the yard.  This was a big hit! The team to collect the most taxes was in the "Kings favor".   King Richard then told them they didn't collect enough taxes and would have to wear a "ball and chain" for their lack of effort.  These were black balloons with 2 foot strings tied to them. They were tied to their ankle and the opposing team had to stomp on their "ball".  This went very quickly and some balloons popped before they started.  Have the children hold them until it is time to start. Also have enough for a couple rounds.  The last event was "knight training".  We hung a string about 8 feet up across the yard. We had printed out 2 large pictures of a dragon and taped them on cardboard. We hung the cardboard from string onto the string across the yard.  They kind of blew around in the wind which made them more challenging to hit.  We gave each child a plastic sword that collapses ($1.80 each at U.S. Toy) and a person from each team had to run and hit the cardboard dragon 3 times then run back (like a relay). This was an even bigger hit than the coins! After about 3 rounds we determined the red team the winner.  King Richard dubbed each one a knight (he had a sword that he tapped on both shoulders and said "You are a knight in my kingdom.  Go out and serve me well.") and then we placed gold medallions (.80 at U.S. Toy) around their neck.  Each child was beaming when they were knighted.   We invited the parents (which most came and were glad they did).  We served chicken drumsticks, grapes and loaves of bread (which they had to rip, no slices).  I made a brownie castle by stacking two layers of brownies (the top one slightly smaller).  I then placed Oreo ice-cream cones as the towers and we cut out little flags from fruit rollups.  We also used tootsie rolls for the top edge of the castle.