I have recently been using the wikipedia module to determine a random wikipedia page.
I have been doing this with a very large list of words, and the random.choice()
One obvious way would be to download a complete list of Wikipedia page names and use that instead of your word list. That would also be much kinder to Wikipedia's search engine which you don't need to get a random page (and besides, if you want a uniform random page, you mustn't use the search engine).
A less-good but perhaps easier fix would be for you to simply try/except the DisambiguationError and try again.