Every time I try to boil a pot of water to make spaghetti, I leave the kitchen to go do something else (I am very busy lol). Sometimes I come back to find the pot boiling over and a mess on my stove! Is there some way I can make the water boil more slowly so I have more time to run my errands?
Turn the temperature down - Once the pot reaches boil, it takes a lot less energy to keep it boiling, turning the temperature down it will keep it from boiling quite so violently.
Don't overfill your pot - Makes sure you are using a pot large enough to handle all the water and pasta
A teaspoon of oil will also help - This helps keep the water from building the bubbles causing it to foam over. When you cook spaghetti, do you add olive oil to the boiling water?
Use a small kitchen timer. Set it for the time takes your pot of water to boil, and put it in your pocket or on lanyard. Then "errand away" until it beeps
Nice timers at http://www.dealextreme.com/products.dx/category.1013~search.timer from credit card to apple sized
This works for anything of course, not just boiling water. You can bake cookies, and still "errand away" :-)
Add some salt and a little olive oil when putting the water to boil. As it will make the water more dense it will boil a little harder than regular water. The olive oil is also good to prevent the pasta from getting stuck to the pot and the salt you need it dissolved so it can be absorbed by the pasta.
Actually, I think the answer is very simple: leave the lid OFF.
There's a lot of other answers here that may be missing a beginner's bad approach to boiling noodles. We often use a lid to decrease time to get to boiling, but once you add the dried pasta and fluff it to keep it from sticking together, don't return the lid back onto the pot.
When cooking pasta, you should actually pay attention and leave on high for a minute (or so, depends on your rangetop) until boiling resumes, and then lower the heat. After that, your attention can wane until the final timer goes off - not that you should leave the house, haha.
Some recipes actually call for turning the heat off at a point in the process to preparing noodles, similar to my favorite method of cooking corn on the cob, hard-boiled eggs, or even when boiling potatoes for mashed potatoes. As an aside, though turning the heat off isn't my norm in practice, it's a great way to more precisely time perfectly "al dente" noodles (or more precisely reaching any desired texture, for that matter). Or, if you insist on having a lid on the pot for whatever reason, cant it so the steam can escape.
Leaving the lid on, with high heat, can actually cause other of starchy and/or "glutenous" things to boil over, such as oatmeal.