Look at some of Poul Anderson's stuff.
Holkas! Polkas! comes to mind as fun reading:
http://www.webscription.net/p-209-hokas-pokas.aspx
Also you might enjoy
The Compleat Enchanter by L. Sprague de Camp as well as the modern day revival of the Harold Shea stories titled
The Enchanter Completed. Sold over at Baen:
http://www.webscription.net/p-129-th...completed.aspx
Also the old
Stainless Steel Rat stories are light hearted and fun but lean toward more of the ray guns and rocket ships SF.
And I would confirm the Hal Spacejock books are a very fun guilty pleasure sort of read. Simon Haynes, the author, visits the board here now and then for a fun time. But there are oodles of light and fun reads that are not the brooding apocalyptic style that is very popular today. I admit I like books with that underlying theme these days. But I am always drawn to fun reads as well.
You know, Ben Bova also comes to mind. He can be funny as heck!! Any of his novels is recommended:
http://www.webscription.net/s-10-ben-bova.aspx
Hour of the Gremlin & Laugh Lines are a nice duo.
The Sam Gunn Omnibus is a very fun time but it too is a ray guns & rocket ships SF.
Piers Anthony is good as well. I recently read
On a Pale Horse again. It's a but dated these days but is a nice silly read about someone who is sort of tricked into filling the recently vacated job of Death. Really it is a lot more light hearted than it sounds. He is a really funny writer. His
Blue Adept novels are very enjoyable without a doubt and I highly recommend them.
I am not sure what B&N or Fictionwise have from him though. But if you use the desktop version of Kindle Reader and Calibre with "the plug-in"
winkwink there are a number of his books over on Amazon:
http://www.amazon.com/Piers-Anthony/...r_dp_pel_pop_1
The are not out in ebook form yet but the whole set of Callahan stories by
Spider Robinson is one of the most entertaining reads for me in a long time. I began with
The Callahan Chronicles followed by
Callahan's Key,
Callahan's Con then
Lady Slings the Booze and a couple others. It's odd they are not in ebook form because Spider is a net sort of guy but I sense he has a predilection for printed matter over bit-streams. So, it's Audible audiobooks or printed copies. I can vouch for the Audible editions, well read and FUN to hear different voices.
I could go on but that's a nice grouping.