Current research: I am involved in a series of high-precision experiments involving muons:

Muon g-2: a proposed next-generation measurement of the muon anomaly to a precision of 0.14 ppm, which will be a sensitive test of the standard model.
MuSun: will measure the rate of the semileptonic weak process μ + d -->n + n + νμ . The rate will impact several fundamental reactions of astrophysics interest, such as solar pp fusion and the n+d reactions observed in the Sudbury Neutrino Observatory.
Mu2e: a future experiment to probe charged lepton flavor violation at a single event sensitivity of 1 part in 10 to the 16th!, which is a very sensistive test of the standard model

Recent completed experiments:
MuLan: a 1-ppm measurement of the muon lifetime, which determines the fundamental Fermi constant to sub-ppm precision.
MuCap: a precision measurement of the rate of the semi-leptonic electroweak process μ + p --> n + νμ, which will determine the least-well-known of the charged weak form factors of the nucleon, the pseudoscalar gp, to 7%.