Looks like plenty of people were happy to take the red pill and plunge back into the Matrix. ''The Matrix Reloaded'' grossed $42,475,000 on its opening day Thursday, AOL Time Warner CEO Dick Parsons announced on Friday. (AOL Time Warner is the parent company of distributor Warner Bros., as well as of EW.com.) Of course, ''Reloaded'' was all but guaranteed to have the biggest opening ever, since it's playing on 8,500 screens in 3,600 theaters. That $42 million figure tops the previous opening day record, set last year by ''Spider-Man'' ($39.4 million), and it puts the movie on track to challange the three-day opening record of $114.8 million ''Spider-Man'' set during its first weekend. Imagine the grosses if Keanu Reeves' Neo could shoot webs from his wrists.