Found your previous post, you may have gotten this from the original thread info but it's not leavening, yeast, or fermentation that is forbidden -- it's products made from grains that have the 
potential to leaven (that have been exposed to water for more than 18 minutes before baking). Matzah is made specially from grain that has been kept dry, and is mixed and starts baking in under 18 minutes. There's five species of 
chametz, fully forbidden grains: wheat, rye, barley, oats, and spelt. These are impermissible both to eat and to
 own during Passover, regardless of your traditional background, and have to be disposed of or sold.
Some traditions (Ashkenazi most prominently) also hold that 
kitniyot, other grains such as rice, corn, beans, etc. should not be consumed, but do not have to be removed -- so you can still feed them to your animals during Passover.
Leavening agents, yeast, and other fermented foods are not forbidden -- if it was, there would be a big problem with the four cups of wine we drink during the Seder 
The specifics of what is, and isn't kosher for Passover are fairly complex and vary with different traditions and denominations, along with the reasons for these restrictions. The story of honoring Jewish slaves escaping from Egypt who didn't have time to bake proper bread is a bit of a misconception, since the abstinence from leaven was instructed to start 
before the Exodus began. A prevailing interpretation is that making bread is an act of creation, something demonstrating 
human power and skill, while Passover is about humbling ourselves and reminding ourselves of God's power.
And yes, Passover is April next year, Yom Kippur is in just a few days, then Sukkot and Simchat Torah.