Being that you are now 30, you will probably want to celebrate a little differently than when you were in your twenties. If you have a family of your own, you may want to make it a family affair for your birthday party with friends and relatives. If you are still single, it's not too late to be a party animal. Your invites could be formal or by email, casual or fun. You're an adult now; it's up to you. Plan a regular party or one that is casual but make it lots of fun with plenty of good party food, drink and party decorations. A cake that reflects the personality of the person celebrating would be fun and interesting. For instance if the birthday girl has big boobs, the cake could be made in the shape of big boobs with flat chocolates for the nipples. Or a giant cookie decorated with sprinkles for all to take a bite out of, or break a piece. 30 are probably the best age to be. Older enough to know better and young enough to do it again. Party-on!