*included in this guide is a way to enter the human contest and get harold disqualified, so you know*
Have Laverne go to the Chron O' John and have Bernard give her the Fake Barf and the Fork. Also, have Hoagie give Laverne the Spaghetti which will become the Wet Soggy Noodles. Now have Laverne go into the big door and talk to the Blue Tentacle to get the Name Tags. Head upstairs to the second room with the Mummy. Get the Extension cord next to the Pink Flamingo. Get the Roller Skates on the table and then use them with the Mummy. The Mummy will be with the other contestants so put a Name Tag on him and he'll be your human for the contest.
Go up to where the contestants are and use the Fake Barf on Harold to get him disqualified. Use the Wet Soggy Noodles on the Mummy. This won't be enough to have him win Best hair, so use the Fork on him to make his hair better. Go to the right and have the Judges do the Best Hair portion of the contest and you'll win.
The next phase will be Best Smile. Have Bernard give Hoagie his Textbook. Then have Hoagie go upstairs to where the Horse is. Use the Textbook on the Horse to bore him to sleep and take his Dentures he left in the glass. Give the Dentures to Laverne and then have her put them on the Mummy. Ask the Judges to do the Best Smile contest and the Mummy will win.
For the last contest, give Bernard the Scalpel. Go into the convention area and use the Scalpel on Oozo the Clown to pop him and take the Box 'o' Laughs. Give the Box 'o' Laughs to Laverne along with the Booboo-B-Gone and attach the Box 'o' Laughs to the Mummy. Ask the judges to do the Best Laugh portion and you'll have won the contest along with the Dinner Certificate.