Sorry, “2 tablespoons plain white vanilla” should be “2 tablespoons plain white vinegar”. And yes, no eggs. It’s vegan! (Although I’m not.)
Another vote for this one. Mike, one of my best friends, was taught how to make cakes by his grandfather, who used to own a cake decorating business–and it’s all about using an out-of-the-box cake but making your own frosting. For my birthday this year, Mike made me a cake with chocolate ganache frosting. Omigod.
And yet, strangely enticing when you’ve got a Nilla wafer in one hand and a can of frosting in the other…
I STRONGLY disagree with using a box cake. I don’t know what it is about them, but no matter how doctored they are the taste of box cake shines through. If you don’t mind the taste of box cake then fine, but I know I’m not alone saying this.
I was at my second cousin’s girlfriend’s house and she served a cake, saying how long she slaved over it, and as soon as I tasted it I just knew. She’d added liquor and cherries and a really nice glaze, but it couldn’t hide that flavour. I asked her if she’d started from box cake and she was shocked I could tell.
Today I baked the lemon cake Lunar Elf linked to!
And I made my own glaze!
It is cooling now and promises to be a fabulous end for our dinner this evening!
Thank you all for your advice and links and encouragement.
(But I don’t believe I’ll be switching to box cakes anytime soon!)
Thanks again.
Congratulations! May these be the first of many fabulous cakes that come out of your oven. 
Store bought frosting? What on earth are you talking about? There is no such thing. 
For reasons that totally baffle me, however, Betty Crocker and Duncan Hines have lent their name to a spackle manufacturer, who for inexplicable reasons has chosen to claim the spackle comes in “flavors”. As this is sold in the grocery store, I don’t trust it, and prefer to go to the hardware store for my drywall-repair needs. 
Anyway - get a copy of The Cake Mix Doctor. This book has a pretty good discussion of the development of mix cakes and why they produce a pretty decent result, and are nearly fool-proof. The rest of the book is a ton of recipes that start with a cake mix, then get improved.
To my sorrow, I actually haven’t made any of the recipes, but they all look pretty good.