Thank you very much for your entries. Of the two, I like #18 better. However, the face on the robot barrel looks a bit too angry. Could you make him happier please? Also, if you are going to use two different fonts for the name of the event, please use a 'techy'-looking one for the 'Tech' part and a German-looking one for the rest (i.e. 'toberFest').
Also, as much as I like this design personally, I don't think it is going to be very appealing to girls so could you come up with something that shows the party, which will be the most amazing event EVER, is for everyone?
I hope that feedback helps, but let me know if you have any questions.