We had our daughter's 3 year old part in Nov. We don't have many family members here in the area. So, we had our friends in our playgroup come over (4 other kiddos) with their mommies at noon on a Saturday. We had Dora and Diego as our theme. We played pin the watch on Dora (found at party supply store), ate "lunch", put together Dora cupcakes (from the website...assembled frosting, hair, etc.), ate cupcakes and opened presents.
I tried to discourage presents by asking our friends to bring donations to the local animal shelter. I wish everyone would have complied. My daughter cried because she was so confused as to getting her gifts and then her little confused friends wanting to take them from her to play, too. Such a rough age and concept. She LOVED taking the donations to the shelter.
We then had the family party (only one set of grandparents and then babysitter and her family over) during dinner time. We had more cake and opened their presents.
Keep it SHORT and SIMPLE. Don't overplan the activities and schedule twice the time you think it will take for each activity. Keep it under 2 hours....and closer to 1.5 hours.
We did make up Dora party bags for the friends and my daughter. Good luck and HAVE FUN!