I'm looking for some fun mods to screw around with, I'm not looking for anything that changes the dynamic of the game or anything unless you have a really good one.
Minecraft mod to try out?
Consider Open Blocks. It adds a lot of really useful, but not dramatic blocks. My favorite example is the trapdoor it adds, which acts like a ladder when it is opened.
Carpenters Blocks adds special tools that expand the blocks you can decorate with a hundred-fold. It even lets you make slopes.
Extra Utilities is becoming a more serious mod, but it too is a collection of miscellaneous blocks, most designed to work with other mods or just be useful. One of my favorites here (other than the quarry) is the Trading Post, which shows you what ever nearby villager is trading without you having to talk to each one.
Thermal Expansion is the easiest technical mod to get into. It can easily increase your resource output without significant worries.
Tinker's Construct lets you make custom tools. It even lets you enchant tools with materials (sometimes *expensive* materials) instead of levels.