BTW one thing to look into about the calculator -- choosing skills like Stats never seemed to add to HP and such, same with UB's Inner Beast adding to speed or attack speed.
Recommendations:
-Click on a single chosen skill to remove. For added fun in coding it, select level IV when none are chosen to also add I-III, and similar for removing (your choice as to whether picking level I when later levels are chosen will reduce it to I or remove them all!). Maybe double-click for those since the buttons are dimmed when the prerequisites are not selected.
-Change the output for the attack time in calculator to have a negative sign before the percentage modifier instead of positive, since it's a reduction in the time.
-Work in the hidden ability numbers like the actual percentages for TB's auras.
If you really wanna turn this website into a timesink , add a mana drain calculator so you can test out, for example, how many times UB could Spit with the chosen items, with effects like Essence of Magic giving a free Spit every cooldown worked in.
This is what I was working on before my disappearance last time, it required quite a lot of work to restructure abilities to allow them to have effects (originally the site was just built to settle a dispute over item stacks, and turned into a whole lot more). Luckily all that code has survived so all I have to do is build on top of the improved data structure which appears to be quite well done.
I am focusing on just duplication current functionality, but the next feature you'll likely see is a pretty vastly improved calculator that not only takes into account abilities as well but any trinkets or skills that you can activate will be toggle-able (especially handy for those trinkets with passive as well as active buffs) it's a lot of weird math I'll have to get my head around again (how things stack, crit limits etc) but I think it'll be worth it for something that should be considerably more accurate.
I was also working on including hidden information like the values of TB's Aura as well as the damage/health of minions and towers into the tool-tips so this was immediately visible as well as included in calculations.
Additional ideas that may or may not ever exist depending on how the world spins at any given time:
- Copy/paste ability at one point so that you can copy paste from the site to settle disputes on forums or such. This may simply be some sort of new visualization of the data in, say, encyclopedia format or such so it can easily be copied from there, or something sneakier that lets you copy tooltips or whatever, I will do whatever fits best at the time.
- Ability to join multiple builds to a single "strategy" so that you can make one at level 5, level 10, level 15 etc and then link them in your strategy to show the different items/abilities chosen at each stage. You could do one for all levels through 1-20 if you supposed.
- Some sort of community features such as "Popular Strategies/Builds" or "Highest Rating", let people comment on your strategy or build etc right on the site to get feedback/criticism.
- Possibly some sort of "amendment" system, which allows people to send me change requests, such as updated item information, or even a new demigod if it is added, and then I can approve (to avoid people doing whatever the hell and ruining everything) the changes and they will go live, so even if I disappear again the onus won't fully be on me to have to make the changes. The biggest flaw in this system is the images are quite difficult to obtain (no so much maintain, but resize and name correctly etc), so I'd probably still have to do that bit 
- Accounts. Not required until you want to save a build or comment (to reduce spam), would be very simple to avoid being too intrusive, would mean we can uniquely identify posters of builds and comments which I think is important in any site to avoid people posing as one another etc.
- Save Build: Can I get a show of hands from anyone that reads this, would you prefer like some talent builders where it will just create a unique URL you can share with people, where you don't need an account or anything to save. Or would it be better to enforce a quick and painless sign-up when you go to save so that all builds can be linked to someone? I'm sure there will be two camps; people that hate signing up for things, despite having signed up for this forum. And those that would like their name linked to their builds so that people don't go stealing them or whatever. I will mention that requiring an account would be easier to code as I can just store all the builds in a database rather than having to generate a unique URL that can encode and decode the state of the site. I'm tending to lean towards accounts because they will be required if any additional functionality is included in the future such as the above mentioned community features.