While the Electoral College in principle "rigs" the presidential election, in practice we've had only four instances where the Electoral College result didn't follow the popular vote (most recently in the 2000 election of George W. Bush).
In contrast, gerrymandering of Congressional districts significantly "rigs" the proportionality of representation in the House.
Example: although collectively Democrats won House races by over one million votes (suggesting Democrats should have at least 51% of the seats), instead the GOP holds 56% of House seats.
Example: although 52% of voters in Pennsylvania voted for Barack Obama in 2012, suggesting Democrats make up around 50% of the electorate, 13 of Pennsylvania's 18 House seats are held by the GOP, making Democrats only 28% of the state's Congressional delegation.
