I don't know about the best pitch but I can certainly share one with you that I use when cold canvassing:.
Have a table with cards and leaflets at my local shopping mall and a catchy slogan. When someone looks the slightest bit interested ask them:
"Have you ever wondered how you could make a little extra money on-line with little to no investment?"
"What would you say if I showed you that you could start your own on-line business with an extensive training program and all the marketing tools you need to succeed all free?"
"Is that something you think you would be interested in?"
If yes, start to show them on your laptop what SFI and TripleClicks is all about. Show them how they can set up their own store or sell other ECA's products. Explain that you will be there personally to guide them through and how you have an incentive program in place for all your active members. This way you will have already formed a personal relationship with your new PSA and they will have the memory of your encounter every-time they see your name at the top of the page.