Personally, I think any time's a good time to buy Lisa Brown's Baby, Be Of Use boardbooks. Why waste your baby's precious time teaching him to sit up, when you could be focusing on far more beneficial skills like making me a drink, fixing my car, doing my banking, or making me some breakfast?
Now is an especially good time to buy the complete, Baby, Be Of Use bundle from McSweeney's because it's on sale for a bafflingly low $16.80, 30% off the regular retail price of $24. Also, McSweeney's got screwed out of $130,000 when their distributor went bankrupt, and so they're selling anything that's not bolted down this week. [Next week: the bolted down stuff.]
Buy stuff like funny board books and McSweeney's Quarterly Concern, emphasis on the 'concern' at McSweeney's Store [mcsweeneys.net via kottke]
Previously: other suggested titles in the Baby, Earn Your Keep series