Do a themed party! They can be a lot of work but they are heaps of fun, plus it means people get to dress up for the party. You can base it on a movie, an idea, a time period or even just a color. You pick your theme then search out cheap decorations and food that you can easily change to fit the theme. Adapt games so that they include the theme as well.

Pin Interest is super helpful in finding themed DIY stuff (do it yourself).

Suggestions for themes:

Gender reversal (guys dress as girls, girls dress as guys)

Alice in Wonderland

Ninja Party

Star Wars

Hunger Games

70's Party

Harry Potter

Crazy Hair Do

Corn toss (where you throw the little pouches into the hole on the board) is a really fun outdoor game. Badmittin(or however you spell it) is fun, and so is just kicking around a soccer ball. You could do sparklers if it's at night.

Have some food. Ordering pizza is always good, and finger food is a must. If it's at night, you could have your dad set up a campfire and roast marshmallows.

So I need help. My birthday is in April and I want to have a birthday party. Im thinking about inviting 20 of my friends (both boys and girls). However I don't want to spend a lot of money on it. I dont have a pool at my house but i have a pretty nice sized backyard for a party. What are some fun things we could do? Please help!