To be honest, lightnovels don't make me laugh all that often. I assume that is because of the slow delivery (limited by my reading speed) compared to anime for example. So I'm mostly grinning stupidly or in rare cases chuckling a bit when reading a funny book.

The series that makes me grin and chuckle the most, though, is Tearmoon Empire. Volumes 1-9 were translated in such a witty manner that there are parts that I unironically compare to Terry Pratchett's prose -not consistently, but the moments were there. Sadly the magic is gone now after a translator switch, but I don't want to get started on that again.