Children who are turning two usually will not be able to play organized games. I have several years experience working with two-year-olds as a teacher and nanny AND did a part-time gig planning b-day parties for awhile. My best advice to you would be to keep it to three - five children unless she is in preschool or day care and is used to being around large groups of kids. Also, most two year olds have short attention spans so have several things for them to do, but only offer two or three choices at a time to avoid overstimulation.
I don't know whether you have a yard to play in so here are some ideas for both.
*Dress-up, clothes, hats and accessories for both boys and girls is good for indoor or outdoor play.
*Toddlers and two's love balls - provide a wide variety of textures and sizes for outdoor play or nerf for indoor play.
Even a wading pool full of ballls.
*Sand and water play for outdoors - fill one wading pool with sand and other with water and offer toys.
*BUBBLES for indoor or outdoor play
*Music and dancing for indoor or outdoor play. Children's CD's can be checked out for free at the library.
*Free art for indoor or outdoor. (Crayons, paper, collage materials and glue sticks. I would avoid paint if more than three kids are comming.)
*Just let them play what ever they want.
*Story time - A short (3-5 minute) story
*Sing songs and music and movement games inside or outside. (Again check the library for CD's - Greg and Steve Musical Movements is fun with this age)
*Type "activities for toddlers and two's" into the google search bar and you'll get craft, music, etc ideas up the wazoo.
Also, recognize the symptoms of over stimulation and quickly convert to a quiet activity if you notice any. Try to keep the party under two hours, and 10 am or soon after nap are the best time for young children to be socializing with eachother. My daughter will be two in November and if the weather is nice that day we are going to have a party at the park so there is built in entertainment, lol! Good luck!