  Using standard methods (due to Janson, Stein-Chen, and Talagrand) from
probabilistic combinatorics, we explore the following general theme: As one
progresses from each member of a family of objects ${\cal A}$ being "covered"
by at most one object in a random collection ${\cal C}$, to being covered at
most $\lambda$ times, to being covered at least once, to being covered at least
$\lambda$ times, a hierarchy of thresholds emerge. We will then see how such
results vary according to the context, and level of dependence introduced.
Examples will be from extremal set theory, combinatorics, and additive number
theory.
