That being said, this is a very easy and fun costume to put together.
The only materials required are:
- A wheelchair (call around to various drug stores and pharmacies - I was able to rent one for 30 days for less than $40).
- A portable DVD player with remote (in the world of laptops/netbooks/tablets, portable DVD players and extra batteries are extremely inexpensive)
- Willow Talk text to speech software - this text to speech software has a voice identical to the one used by Stephen Hawking's (unfortunately, this software has been discontinued, but versions can be found through search engines).
- A blank CD or DVD
- Zip ties
Use Willow Talk to create MP3s of everything you might want to say throughout the evening. Try to think ahead to every conversation you might have - greetings, discussing costumes (your own and others), ordering drinks, humor, etc.
I organized all of these sound files into folders based different conversational categories.
Some of the basics I used to start were: Yes, no, thank you, hello, how are you, I am fine, please, sorry, I am Stephen Hawking, a brief bio of Hawking, could you please rephrase that so I can answer you better (this is a good one if anyone throws you a conversational curve ball), could you please make that a yes or no question, etc
I also had a number of quotes from Stephen Hawking ranging from quick one liners to rather large in depth speeches and theories.
For humor, try adding some songs by the hip hop parody MC Hawking.
Use your imagination - the more things you are able to say, the better the costume will be received.
Once you have a decent database of phrases built up, just burn them to a disc, zip tie the portable DVD player to the wheelchair, get comfy, chose what want to say by subtly using the player's remote control, stay in character and have fun!
Be sure to bring along some extra batteries and someone very patient who is willing to push you around for the evening.