Let G be a finite group.  A representation V of G is said to be unisingular if det(1-g) = 0 for all g in G.  Unisingular representations arise naturally in arithmetic via point counts on curves over finite fields and l-adic representations on abelian varieties.

In this talk we will survey recent work on properties of elliptic curves and higher dimensional abelian varieties with unisingular l-adic representations with an emphasis on explicit calculation and construction.   Some of this work is joint with John Voight, Jeff Yelton, and Meagan Kenney.