DNA Microarrays have a wide variety of potential exciting applications in medicine, life sciences, and the commercial arena. The exploitation of these applications depends on developing novel and sophisticated computational methods to handle the experimental data. In this talk we shall present two such methods: We first present a novel clustering algorithm for analysis of gene expression data, called CLICK, which is shown to outperform extant clustering methods. We then demonstrate how novel algorithmic ideas can extend the use of universal 8-mer oligonucleotide chips to sequence targets several thousand bases long, even in the presence of hybridization errors, using a reference sequence.