Well, I was waiting to see what ideas everyone else had, but here's the core components of my method:
14th level wizard
Spell Matrix (7th level Sor/Wiz, from Spell Compendium)
Twin Spell (Metamagic feat, from Complete Arcane)
Action Surge (feat from Eberron Setting)
For starters, when you prep for the day, memorize spell matrix, and two twinned 3rd level spells. Hopefully you have an Int high enough to get the bonus 7th level spell...it's not too hard to afford a +6 stat boost item at that level.
During the day, when combat seems to be likely within the next two hours or so, store two 2nd level spells in the spell matrix. Scorching ray is a good choice for damage, or you can go with glitterdust or cloud of bedevilment if you're trying to force as many saving throws as possible. Per the rules of spell matrix, you can release both spells as a single swift action if they're both 2nd level or lower.
When combat starts, activate the spell matrix to launch the two 2nd level spells, then cast one of your twinned spells. After that, spend 2 action points to take an extra standard action during the round, and cast the other twinned spell. You can either go the direct damage route with things like fireball, or take spells like slow and stinking cloud to maximize the number of saves your opponents have to make.
Sorcerers have to take a full round action to cast metamagic, so they can't pull the twinned spell trick using the standard action from Action Surge. That drops the total number of spells they can throw in a round to 5. However, they do have more spell slots, so they can do this trick more than one fight per day...