I tried potholing once and was terrified to be squeezing myself into sunken crevices of rock with no light, with plenty of green slime under my hands and knees.
I vowed I would never take another trip underground, but I have changed my mind, virtually of course.
At goodearthgraphics.com/vitcave you will be able to uncover the many dark and damp mysteries of the world of caves. Plus, you do not need to don a jumpsuit and headlamp in order to enjoy them.
Keen caver and photographer Dave Bunnell has amassed this vast collection of information and pictures from his 35-odd years of experience underground. The site is split into four key sections covering the different underworld realms.
When taking a virtual tour in pictures and words, you can find sights like the incredibly cool glacier caves in Alaska and Nepal show, and some hot and steaming action inside lava tubes.
This site has a veritable feast of classroom fun that I certainly wish I had had the chance to watch when I was in school - then I might not have done quite so badly at the sciences.
The periodic table is one of those cumbersome things that you just have to learn if you want to do well at science. But how can one get enthusiastic about a bunch of nonsensical letters laid out in a grid?
The answer could be a site that academics at the University of Nottingham have put together. It has a video explanation, including cool scientific experiments for each of the chemical elements in the periodic table.
Far from being boring and nonsensical, these guys make learning about science look fun.
This site is aimed at people who travel alone, be it for work or pleasure. It recommends things to do in London, places to eat and relax without feeling uncomfortable about being without a companion.
The editors have reviewed a range of activities and locations which have been grouped into the categories: table for one, play for one, away for one and spa for one. As well as the many London-based recommendations, away for one takes the wider world under its wing.
You will need to register, which is easy and free and then you can start perusing the suggestions from Paris to Brazil and beyond.
There are pictures and comments from the sites reviewers, and often booking details and special offers for users of the site.
Bear in mind that you are under no obligation to book the trips in this way if you can surf around for a better offer yourself.
How much of a nerd are you? If you are reading this there is at least the chance you have leanings towards nerdiness. And you can find out much by pointing your browser to nerdtests.com.
There are two main categories of tests - those created by the site and those created by users of the site. Click "NerdTest Tests" for the site generated ones and choose which test you want to take.
My favourite is the basic The Nerd Test. I scored 95 which makes me a nerd god. I am not sure if I should be proud or ashamed. Use the text at the end to embed your result into a website or blog and share your rating with the world.
It is worth bearing in mind that the user-generated tests might have content or language which could offend. However, there is a rating filter that will warn you about this before you enter the test, so click at your own risk.
And if you think you can make a better test, well go ahead and click the appropriate link. But do not forget to send it to us if you do.