We give a new construction of pseudorandom generators from any one-way function. The construction achieves better parameters and is simpler than that given in the seminal work of Haastad, Impagliazzo, Levin and Luby [SICOMP '99]. The key to our construction is a new notion of next-block pseudoentropy, which is inspired by the notion of ``inaccessible entropy'' recently introduced in [Haitner, Reingold, Vadhan and Wee, STOC '09]. An additional advantage over previous constructions is that our pseudorandom generators are parallelizable and invoke the one-way function in a non-adaptive manner. Using [Applebaum, Yuval and Kushilevitz, SICOMP '06], this implies the existence of pseudorandom generators in NC^0 based on the existence of one-way functions in NC^1.