The hypothetical subjunctive is the mood of the verb used when something hypothetical is being proposed.
"It would be interesting if President Obama were to announce a new running mate for the 2012 election."
"I suggest you look into this business proposal carefully before investing in it."
Each situation describes something that isn't happening, hasn't happened, and isn't guaranteed to happen - just the speaker's imagination or desire.
Side note: I honestly had no idea what 'hypothetical subjunctive' meant until I read your post, and then I looked it up on Wikipedia. Grammar's a very interesting topic, but I'd suggest going by your guts instead of getting entangled in terminology. Sure, we should know what a verb is, but in this case the 'feel' of a sentence is more important than worrying about jargon. It's also faster!
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