Projectile toilet water! WHAT??

I must prefice this post by saying that these are the things that happen on television or to ME! Yesterday morning (Emma's birthday) I'm getting ready to do a load of laundry when I hear a loud whooshing sound coming from the drain of our laundry sink. I try to locate the source of the noise and finally figure out it's actually coming from the plumbing pipes. I attempt to run some water down the drain, which makes the noise stop momentarily however it starts back up after about 1 minute. Next I hear this loud swirling, whooshing, "this isn't good" noise coming from our basement bathroom. I turn around and look in the bathroom just as water starts arcing.....yes projectile arcing out of the toilet......water, pee, toilet paper and other unmentionables start FLYING out of my toilet!!! I mean we are talking 5 feet out the bathroom door into the laundry room. Well of course me and my calm self proceed to FREAK out. I holler at the kids to head upstairs thinking we are about to have a major problem on our hands. Morgan yells from the main floor that the other toilet is also shooting water and other lovely things! At this point I'm at a complete loss for words.........Emma is crying and complaining that it STINKS really bad and it's ruining her birthday. I finally put 2 brain cells together and call our city public works department. A gal answers in a nice friendly hold music voice and I holler over that phone that there is something horribly wrong at 4934 Grand St. She puts me on HOLD then comes back in her ultra pleasant voice and says...,"We have a sewage vacuum truck in your area and it must be creating some back pressure/suction that is allowing sewage water to spew from your toilets." She then tells me I have to get up on my roof and check the plumbing vent pipe to make sure that it's not clogged. I could go on and on about the 4 hour ordeal that transpired, but I'm sure you get the point. I guess I never knew how fitting the name of our blog (Helfer Havoc) would be until yesterday!! All is back to normal (like that word ever describes our household!) and we were able to celebrate Emma's birthday.