Call to the masses
Get your guests geared up for your festivities by sending out fun invitations or Evites at least three weeks prior to the date of your bash. Don't assume the party has to be on Memorial Day itself; some partiers like to get the party started on Saturday or Sunday. That way, they have Monday to recover before heading back to work!
If you are planning a potluck-style party, give guests the heads-up in advance and coordinate a list so that you don't end up with a full buffet of chips, dips and brownies. Plan on providing a main entrée -- whether it be simple burgers and dogs on the grill or something fancier like grilled beef and vegetable kabobs -- then direct guests on the items you need to complete your menu, such as a few appetizers, some specific side dishes and even sodas, paper plates, cups and napkins. In today's economy, guests will understand and be happy to pitch in. Keep in mind where you're serving the food and what you'll need to do to keep it hot or cold.
Delegate, delegate, delegate
If you are cooking the day of the party, assign your co-hosts a few tasks to keep the party flowing smoothly. Let your man handle the grill, while you take care of refilling guests' drinks or taking their purses/keys as they come in the door. Also, assign someone the task of playing music and gathering guests to join in a fun game.
Spruce up the place
A party is always more fun with decorations, so hit up your local party supplies store. You can go many different directions here. Just be sure to choose your theme before your invitations go out so you can prepare guests for the fun ahead!
Memorial Day honors our nation's fallen soldiers, so a patriotic theme is fitting. Fly an American flag, encourage guests to dress in their reds, whites and blues, and serve food with Americana flare. Easy cookout foods such as burgers and dogs work well with this theme.
If you are looking to celebrate Memorial Day as the kick-off to summer, go for an island/beach theme. Don guests with plastic leis (one of the biggest bargains in the party store!) and serve beverages in tiki cups. Set tiki torches outside to really light up the party mood when the sun goes down. Go Polynesian when creating your menu: Think potstickers, coconut shrimp, chicken skewers, roasted pig (if you're feeling really industrious!) and fresh fruit for dessert.