Golf

• There are lots of possibilities for the venue of a golf-themed party. Hold the party at your local country club, miniature golf course or in your backyard. If the guests are small, a putt-putt party would be perfect. Older boys could hit the green at the local grown-up golf course or driving range. Decorate tables with fake grass and make cupcakes with candy golf balls and flags on them. Send guests home with a personalized golf ball commemorating the occasion.
  
  

Baseball

• Hit the baseball diamond at your local park for a baseball-themed birthday. Decorate using the colors of your son's favorite professional or minor-league team and blow up balloons and streamers using those colors. Make a round birthday cake and frost it with white icing and red icing "stitches" to look like a baseball. Serve concession-stand-worthy snacks such as soda, popcorn, nachos and hot dogs. Put together a baseball game that pits kids against adults or one team of boys against another. Award tiny trophies to everyone who plays.
  
  

Football

• Host a football party around a big game that the boys can watch together. Set out chips and dips, raw vegetables and dressing, buffalo wings and sliders, along with pizza bites. Once the game is over, the boys can toss around a pigskin outside, then have some chocolate football cupcakes. Give each boy his own miniature football to take home as a favor. Have football trivia questions on hand about the origins of the game and the ball, and famous football athletes everyone knows about. Decorate your home with pennants and jerseys from your son's favorite team.
  
  

Bowling

• While not your typical sport, bowling can be a lot of fun for boys. Head to the local bowling alley and begin the competition. Give everyone a card that allows them to finish the party by playing some arcade games and serve bowling-alley-friendly snacks such as cookies, punch and chips. A bowling pin key chain makes a cute souvenir. The birthday boy would look adorable in his own bowling shirt, or you could get shirts custom-made for all the party guests to form their own birthday bowling league.