I tried to download all the http_requests reports as of today. Out of 2795 URLs, however, 8 failed to download, with status 404:
http://api.ooni.io/reportFiles/2015-01-06/20150106T160035Z-AS22773-http_requ... http://api.ooni.io/reportFiles/2015-04-13/20150413T140425Z-AS22773-http_requ... http://api.ooni.io/reportFiles/2015-04-13/20150413T153956Z-AS3352-http_reque... http://api.ooni.io/reportFiles/2015-04-21/20150421T140026Z-AS22773-http_requ... http://api.ooni.io/reportFiles/2015-04-27/20150427T022702Z-AS3352-http_reque... http://api.ooni.io/reportFiles/2015-05-05/20150505T000230Z-AS29141-http_requ... http://api.ooni.io/reportFiles/2015-05-08/20150508T002621Z-AS48452-http_requ... http://api.ooni.io/reportFiles/2015-05-19/20150519T000031Z-AS29141-http_requ...
Here is what I did. First, downloaded the JSON index of reports.
$ wget -O reports.json http://api.ooni.io/api/reports
Filtered out just the http_requests ones (using the attached script).
$ ./ooni-report-urls -t http_requests reports.json | sort | uniq > ooni-report-urls.txt
Downloaded with Wget.
$ wget -c -i ooni-report-urls.txt