Bay seniors who like to keep their brain synapses firing on all cylinders should check out TED (Technology, Entertainment, Design) conferences where, instead of hours of oratory, speeches are kept to an 18 minute limit. The ideas are arresting and, for the main conferences, so are the prices -$900 and up. This Sunday however, you can get a taste of TED for just $40 at the Sonoma County Day School. Speakers include well-regarded academicians, an author, a singer/activist, a cyclist and a professional anachronist. If you’d prefer to pay nothing at all you can always watch a plethora of previous TED talks on YouTube.