I don't think it would be unreasonable to say, "Consuming no more than 100 kWh of energy (gross, total), answer the following question: ..." I can't think of any really dangerous attacks that this leaves open, but I undoubtedly am missing some.
Since energy cannot be created or destroyed, and has a strong tendency to spread out every which way through surrounding space, you have to be really careful how you draw the boundaries around what counts as "consumed". Solving that problem might be equivalent to solving Friendliness in general.
The Future of Humanity Institute wants to pick the brains of the less wrongers :-)
Do you have suggestions for safe questions to ask an Oracle? Interpret the question as narrowly or broadly as you want; new or unusual ideas especially welcome.