We prove that the alternating group of a topologically free action of a countably infinite group Γ on the Cantor set has the property that all of its ℓ 2 -Betti numbers vanish and, in the case that Γ is amenable, is stable in the sense of Jones and Schmidt and has property Gamma (and in particular is inner amenable). We show moreover in the realm of amenable Γ that there are large classes of such alternating groups which are simple, finitely generated, and nonamenable, and in many cases also C * -simple. Among the tools used in constructing some of these classes is a topological version of Austin's result on the invariance of measure entropy under bounded orbit equivalence.