Include a few sections with various questions on:
Logistics: HVAC, classroom hygiene etc.
Facilitator/s: How well did they facilitate
Learnings: Whether the participants learnt anything
Application of learnings: How do they plan to apply the learnings
Content: Whether the content was in line with business and learner needs
I recommend you decide these questions based on you next steps as this is just the reaction you are gauging.
You may want to decide on the time to gauge the "Learnings" depending on how soon you believe they can imbibe the concepts discussed.
Then you should see if any behavioral changes were noticed or not.
Lastly you should try and calculate the results.
Feel free to write to me or call with specifics of your seminar if you need more help with this.
19th February 2010 From India, Delhi