Vimdeck (GitHub: tybenz / vimdeck, License: MIT) by Tyler Benziger is a plugin for showing presentations. It uses Markdown, and renders headers with fonts that look like FIGlet. Code is syntax highlighted, and images are turned into ASCII art.
Apparently, some plugins like YouCompleteMe generate unwanted error messages that can't be turned off. Hector Arciga wrote a plugin that intercepts these errors and changes the text colours so you can't see them: noerrmsg.vim.
So if you really can't stand those errors, then you can at least sweep them under the carpet by making them invisible (depending on your terminal setup).