The Integrative Genomics Viewer (IGV) is the browser. Data used in Zack et al., Nature Genetics, 2013, and multiple TCGA cancer marker papers.
Tumorscape: Data for Beroukhim et al., Nature, 2010 with copy number profiles for ~3,000 cancers, now available within the Broad copy number portal, under '2011-02-01 Tumorscape'.
Tumorportal: Website with cancer mutation data for over 4,000 cancers, from Lawrence et al., Nature, 2014.