It used to be that getting excited about a calculator was the ultimate sign of geekdom. But now it seems that everybody these days is coming up with a calculator and that people, especially the cool kids, are actually excited to use them. Here are a few that seem worthy of a whirl:

The Low Carbon Food Calculator at eatlowcarbon.org – This was developed by Bon Appétit Management Company which operates lunchrooms at museums, schools and corporations. They will be implementing a new low carbon menu at 400 cafes and cafeterias around the country. Since food accounts for 1/3 of greenhouse gas emissions, calculating the carbon footprint of food is a great idea and a diet tool that even a foodie can get behind. Plus, $100 says there will be a miraculous connection between high carbon foods and foods that make you fat. You can also text LCD and the name of the food to 69886 and get back the carbon footprint when eating out or download a pocket guide (PDF).

Conservation Almanac – This isn’t exactly a calculator, but an online database of land conservation in America, created by the Trust for Public Land. You can search by state or acres conserved nationally, dollars spent on conservation and state conservation programs and policies. One thing I learned, California has made a significant investment in conservation, but public dollars spent have been exponentially decreasing since 2003. It may be time to call the Governator for a little chat.

Home Energy Check-up at Alliance to Save Energy – Self audit your home energy use and find out where you can save money. Rumor has it that they will have a calculator for assessing how much better your car’s gas mileage could be with proper maintenance and driving. You mean speeding and slamming on my brakes isn’t fuel efficient? Say it ain’t so!

Environmental Impact Calculator at Low Impact Living – This calculator shows your carbon footprint, as well as energy, water, wastewater, trash, and storm water runoff footprints of your home and lifestyle. The best part is that it recommends projects based on your specific inputs and a checklist that changes the total based on completed projects so that you can see your progress.

Fuel Cost Calculator – Thinking about getting a new car? Use this fuel cost calculator to figure out the most economical option. A cheap car with poor fuel economy may end up costing you more than you think. Yes, it’s a government calculator, but it’s still helpful.

Paper Calculator at Environmental Defense Fund – Ever wonder if buying recycled paper really makes a difference? Find out here. Print up the stats on recycled paper and give it to your boss to help your company make better paper choices.